阅读说明：本技术 一种选矿厂半自动磨机用进料端衬板及其加工工艺 (Feeding end lining plate for semi-automatic mill of concentrating mill and processing technology thereof ) 是由 朱国伟 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种选矿厂半自动磨机用进料端衬板及其加工工艺,该进料端衬板由以下质量分数的各组分组成：0.705％C、0.242％Si、0.628％Mn、2.15％Cr、0.266％Mo、0.0311％P、0.110％S；本发明所述的一种选矿厂半自动磨机用进料端衬板及其加工工艺,筒体衬板结构改进后,通过改进超高锰合金钢的配方、采用热处理新工艺等措施,很好的解决耐磨超高锰合金钢的淬透性、抗蠕性和耐磨性问题,提高超高锰合金钢的初始硬度和整体机械性能,半自磨机各项工艺指标将有所提高,并与格子板、端衬板同步磨损,一同更换,减少检修次数和事间,避免重复劳动,降低成本,提高效益。(The invention discloses a feeding end lining plate for a semi-automatic mill of a concentrating mill and a processing technology thereof, wherein the feeding end lining plate comprises the following components in percentage by mass: 0.705% C, 0.242% Si, 0.628% Mn, 2.15% Cr, 0.266% Mo, 0.0311% P, 0.110% S; according to the feeding end lining plate for the semi-automatic mill of the concentrating mill and the processing technology thereof, after the structure of the barrel lining plate is improved, through improving the formula of the ultra-high manganese alloy steel, adopting the measures of a new heat treatment process and the like, the problems of hardenability, creep resistance and wear resistance of the wear-resistant ultra-high manganese alloy steel are well solved, the initial hardness and the overall mechanical property of the ultra-high manganese alloy steel are improved, various technological indexes of the semi-automatic mill are improved, and the semi-automatic mill is worn synchronously with the grid plate and the end lining plate and is replaced together, so that the overhaul times and the trouble are reduced, the repeated labor is avoided, the cost is reduced, and.)

1. The utility model provides a semi-automatic mill of ore dressing plant is with feeding end welt which characterized in that, this feeding end welt comprises each component of following mass fraction: 0.705% C, 0.242% Si, 0.628% Mn, 2.15% Cr, 0.266% Mo, 0.0311% P, 0.110% S.

2. The feed end liner for a semi-automatic mill of a concentrating mill according to claim 1, wherein: the length of the lining plate at the feed end is 1410mm, the width is about 440mm, the single-side bulge 80mm of the lining plate is a lifting strip, two bolt holes are arranged in the middle of the lining plate, the hole distance is 870mm, and the lining plate of the barrel body is fixed on the barrel body by two flat-head bolts of M58.

3. The feed end liner for a semi-automatic mill of a concentrating mill according to claim 1, wherein: the thickness of the lining plate of the feeding end is 70mm, the hardness of the lining plate is HRC48-52, and the wear-resistant lining plate is fixedly connected with the cylinder body by adopting high-strength bolts.

4. The processing technology of the feeding end lining plate for the semi-automatic mill of the concentrating mill according to claim 1, characterized in that: the processing technology of the lining plate at the feed end comprises the following steps:

firstly, confirming a product size chain;

step two, manufacturing a mould sample plate;

step three, manufacturing a mould;

fourthly, modeling;

fifthly, coating;

sixthly, preparing a box;

seventhly, checking the size;

eighth step, closing the box;

ninth, batching;

the tenth step, chemical component analysis and component adjustment before smelting and furnace;

step eleven, temperature measurement;

step ten, pouring;

step ten, heat preservation and box opening;

fourteenth, checking the semi-finished product and confirming the performance test;

fifteenth step, removing risers (grinding) and carrying out heat treatment;

sixthly, detecting hardness;

seventeenth, inspecting finished products;

eighteenth, marking;

nineteenth, identify shipments.

5. The processing technology of the feeding end lining plate for the semi-automatic mill of the concentrating mill according to claim 1, characterized in that: the lining plate at the feed end adopts high manganese alloy ZGMn13Cr 1.

6. The processing technology of the feeding end lining plate for the semi-automatic mill of the concentrating mill according to claim 4, characterized in that: during heat treatment, the steel is heated to 1100 ℃ for 4h, heat preservation and water quenching are carried out, and then tempering treatment is carried out at 250 ℃ for 4 h.

7. The process for machining a feed end liner plate for a semi-automatic mill of a concentrating mill according to claim 1, wherein the process comprises machining a feed end liner plate for a semi-automatic mill of a concentrating millIs characterized in that the C content is increased by 0.1 percent, and the α k value is reduced by 39.23-41.19J/cm at normal temperature²。

Technical Field

The invention belongs to the field of liner plate processing, and particularly relates to a feeding end liner plate for a semi-automatic mill of a concentrating mill and a processing technology thereof.

Background

The semi-autogenous mill is the main grinding equipment in the production of fossil power, mine, chemical industry, metallurgy and other industries at home and abroad, and the lining plate and the grinding ball are the main working parts in the normal operation of the semi-autogenous mill. With the development of modern production, the diameter of the semi-automatic mill is larger and larger, and the mill with the diameter of about five meters is widely applied to production, so that the quality requirements on lining plates and grinding balls are higher and higher. Because the lining plate and the grinding balls are in a harsh working condition for a long time, the maintenance amount and the replacement amount are quite large, so that the manpower, material resources and financial resources are wasted, the production efficiency is directly influenced, and the civilized production of modern enterprises is influenced. Therefore, the lining plate made of novel wear-resistant and impact-resistant materials is used to create the optimal working attitude of the semi-autogenous mill, and the lining plate is an important way for improving the yield, reducing the consumption and striving for good economy and civilized environment;

the ore rotates along with the cylinder, the position is rapidly improved, and the ore is rapidly converted from a pressed state to a tension state. When the gravity of the ore overcomes the centrifugal force, the ore is separated from the cylinder and falls, but the falling paths of the ore with various particle sizes are different. The large ore blocks firstly slide down when the upper body reaches a lower height due to the large gravity, impact and grinding effects are generated on smaller particles at the same time, and then the large ore blocks move towards the central layer of the cylinder; the middle ore blocks roll down along the barrel body to a higher position according to the falling state, and the ores are mutually ground and peeled to form a falling area; the small ore blocks fall along the parabolic track when the barrel body reaches a higher position, and an ore fall area is formed. The impact force at the moment enables the ore to be ground into fine particles, the particles meeting the requirement of the product particle size are discharged from the middle part through a discharge end grid sieve, the initial hardness of the lining plate can be mainly solved by adjusting the composition of the lining plate, the heat treatment process and the like, so that the hardenability, the creep resistance and the wear resistance of the lining plate are improved, and therefore, the feeding end lining plate for the semi-automatic mill of the ore dressing plant and the processing process thereof are provided.

Disclosure of Invention

The invention mainly aims to provide a feeding end lining plate for a semi-automatic mill of a concentrating mill and a processing technology thereof, which can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a feeding end lining plate for a semi-automatic mill of a concentrating mill and a processing technology thereof are disclosed, wherein the feeding end lining plate comprises the following components in percentage by mass: 0.705% C, 0.242% Si, 0.628% Mn, 2.15% Cr, 0.266% Mo, 0.0311% P, 0.110% S.

Preferably, the length of the lining plate at the feeding end is 1410mm, the width is about 440mm, the single-side bulge 80mm of the lining plate is a lifting strip, two bolt holes are formed in the middle of the lining plate, the hole distance is 870mm, and the lining plate of the barrel body is fixed on the barrel body by two flat-head bolts of M58.

Preferably, the thickness of the lining plate of the feeding end is 70mm, the hardness of the lining plate is HRC48-52, and the wear-resistant lining plate is fixedly connected with the cylinder body by adopting a high-strength bolt.

A processing technology of a feeding end lining plate for a semi-automatic mill of a concentrating mill comprises the following steps:

firstly, confirming a product size chain;

step two, manufacturing a mould sample plate;

step three, manufacturing a mould;

fourthly, modeling;

fifthly, coating;

sixthly, preparing a box;

seventhly, checking the size;

eighth step, closing the box;

ninth, batching;

the tenth step, chemical component analysis and component adjustment before smelting and furnace;

step eleven, temperature measurement;

step ten, pouring;

step ten, heat preservation and box opening;

fourteenth, checking the semi-finished product and confirming the performance test;

fifteenth step, removing risers (grinding) and carrying out heat treatment;

sixthly, detecting hardness;

seventeenth, inspecting finished products;

eighteenth, marking;

nineteenth, identify shipments.

Preferably, the feed end lining plate is made of high manganese alloy ZGMn13Cr 1.

Preferably, during the heat treatment, the steel is heated to 1100 ℃ for 4h, kept warm, quenched by water and tempered at 250 ℃ for 4 h.

Preferably, the content of C is increased by 0.1%, and the α k value is reduced by 39.23-41.19J/cm at normal temperature²。

Compared with the prior art, the invention has the following beneficial effects: according to the feeding end lining plate for the semi-automatic mill of the concentrating mill and the processing technology thereof, the lifting strip is changed into the middle of the lining plate, the two ends of the lifting strip are uniformly stressed, the trapezoidal strength of the lifting strip is increased, and the lifting process holes are formed in the reinforcing rib plates at the two ends of the lifting strip, so that the installation and lifting are convenient, the scheme is feasible, the height of the lifting strip is only changed for the high and low lifting strip lining plate, and the rest sizes are unchanged; after the structure of the liner plate of the cylinder body is improved, the problems of hardenability, creep resistance and wear resistance of the wear-resistant ultrahigh manganese alloy steel are well solved by improving the formula of the ultrahigh manganese alloy steel and adopting measures such as a new heat treatment process and the like, the initial hardness and the overall mechanical property of the ultrahigh manganese alloy steel are improved, various process indexes of the semi-automatic mill are improved, and the semi-automatic mill, the grid plate and the end liner plate are worn synchronously and replaced together, the overhaul times and time are reduced, repeated labor is avoided, the cost is reduced, and the benefit is improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the feed end liner of the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

The feed end lining plate comprises the following components in percentage by mass: 0.705% C, 0.242% Si, 0.628% Mn, 2.15% Cr, 0.266% Mo, 0.0311% P, 0.110% S.

The length of a lining plate at the feed end is 1410mm, the width is about 440mm, a single-side bulge of the lining plate is 80mm and is a lifting strip, two bolt holes are arranged in the middle of the lining plate, the hole distance is 870mm, and the lining plate of the barrel body is fixed on the barrel body by two flat-head bolts of M58; the thickness of the lining plate of the feeding end is 70mm, the hardness of the lining plate is HRC48-52, and the wear-resistant lining plate is fixedly connected with the cylinder body by adopting high-strength bolts.

During processing, confirming a product size chain;

step two, manufacturing a mould sample plate;

step three, manufacturing a mould;

fourthly, modeling;

fifthly, coating;

sixthly, preparing a box;

seventhly, checking the size;

eighth step, closing the box;

ninth, batching;

the tenth step, chemical component analysis and component adjustment before smelting and furnace;

step eleven, temperature measurement;

step ten, pouring;

step ten, heat preservation and box opening;

fourteenth, checking the semi-finished product and confirming the performance test;

fifteenth step, removing risers (grinding) and carrying out heat treatment;

sixthly, detecting hardness;

seventeenth, inspecting finished products;

eighteenth, marking;

nineteenth, identify shipments.

Wherein the lining plate at the feed end adopts high manganese alloy ZGMn13Cr1, and is subjected to heat treatmentHeating to 1100 ℃ for 4h, preserving heat, quenching with water, and tempering at 250 ℃ for 4h until the content of C is increased by 0.1% and the α k value is reduced by 39.23-41.19J/cm at normal temperature²。

It should be noted that the initial hardness of the lining plate can be mainly solved by adjusting the components of the lining plate, the heat treatment process and the like, so as to improve the hardenability, the creep resistance and the wear resistance of the lining plate, and the method specifically comprises the following steps:

1. the material of the liner plate of the cylinder body of the semi-autogenous mill is selected.

The high manganese steel has good toughness and work hardening capacity. Under strong impact load, the stressed surface is work hardened, and the core still maintains good toughness, so that the requirements of the using working condition of the semi-autogenous mill can be met. However, for the casting lining plate with a thick and large cross section, the high manganese steel also has the problems of insufficient wear resistance, low yield strength, easy creep deformation and extension, and reverse bow deformation caused by surface phase change.

The ultrahigh manganese alloy steel can further improve the strength and toughness of steel, simultaneously improve the work hardening capacity and wear resistance of the steel and overcome the defects of common high manganese steel.

Therefore, the ultra-high manganese alloy steel is suitable for manufacturing the cylinder liner plate of the semi-autogenous mill.

1.1 determination of chemical composition of ultrahigh manganese alloy steel

Chemical composition is an essential factor in determining organization and performance. The high manganese steel belongs to the high alloy steel category, in order to further improve the mechanical property and the wear resistance of the high manganese steel and improve the technological property of the high manganese steel, other alloy elements are added into the high manganese steel for alloying. Alloying has the following three purposes:

(1) refining the cast crystalline structure. The crystal structure of high manganese steel tends to be relatively coarse, and the thickness of the as-cast crystal structure is directly related to the final structure after the water toughening treatment. The coarse, crystalline structure often causes defects in structure and properties, which reduce the mechanical and wear resistance properties of the steel. Certain alloy elements can be added to carry out chemical reaction in the molten steel to form carbide, oxide, nitride and the like. If the compound has high melting point and the crystal structure and lattice constant are similar to those of steel, the compound can be used as the crystal core of molten steel, so that the crystal structure is refined.

(2) The mechanical property and the wear resistance of the steel are improved. The multi-element alloy elements can be dissolved in high manganese austenite, so that the steel is strengthened, and the strength properties of the steel, such as yield strength and tensile strength, are improved.

(3) The process performance is improved. The high manganese steel is subjected to water toughening treatment to form a single-phase austenite structure. Austenite is unstable and easily precipitates carbide during cooling, and the structure of steel changes. If the steel contains more elements for increasing the stability of austenite, the precipitation of carbide can be prevented when the steel is heated, and the complexity of the heat treatment process is reduced.

Basic chemical composition-carbon

The high manganese steel belongs to steel with high carbon content, and the carbon content is 0.9-1.5%. Carbon has two functions in high manganese steel, and first, single-phase austenite structure is promoted to be formed; secondly, solid solution strengthening to ensure high mechanical property. Carbon also has an important effect on wear resistance. When the contents of carbon and manganese are different, different structures are formed in the steel, and when the carbon is low, a martensite structure is formed. The mechanical properties are poor when the contents of carbon and manganese are low. The carbon content is high, and although the cast structure contains more carbides and a small amount of pearlite structure, the single-phase austenite structure can be obtained after the solution treatment. Of course, the carbon content should not be too high, otherwise the carbides cannot be completely eliminated after the heat treatment.

The carbon content in steel has a significant influence on the mechanical and wear properties. The strength of the steel increases within a certain range as the carbon content of the steel increases in the as-cast state. The hardness increases with increasing carbon content. The plasticity and toughness of the steel are obviously reduced. When the carbon content reaches about 1.3 percent, the toughness of the as-cast steel is reduced to zero. This is because the quantity of carbides in the as-cast structure increases with the increase in the carbon content, and even continuous network carbides are formed at the grain boundaries, which greatly impairs the intercrystalline strength and the plasticity and toughness of the steel. The properties of the steel after solution treatment are greatly changed. And water quenching at 1050 ℃ to obtain an austenite structure. Even if the carbon content is increased to 1.48 percent, the impact toughness can still reach 81.395J/cm²The carbon content can reach 196.133-294.2J/cm²。

The impact of carbon on impact toughness is particularly pronounced at low temperatures. For example, in comparison with two steels having carbon contents of 1.06% and 1.48%, the impact toughness is about 2.6 times different at 20 ℃ but 5.3 times different at-40 ℃ and 13 times different at-60 ℃.

The impact toughness of carbon is affected by the range of carbon content. Under the condition that the content of Mn is not changed, the influence of the carbon content in the range of 0.8-1.15% at +20 ℃ is small, and the impact toughness is obviously reduced after the carbon content is more than 1.15%. The following relationship exists in the amount between the increase in carbon content and the change in impact toughness

1) When the carbon content is increased by 0.1%, the α k value is reduced by 39.23-41.19J/cm at normal temperature². This also corresponds to a reduction in impact toughness at a temperature reduction of 15 to 20 ℃.

Although the solution treatment can dissolve the carbide, when the carbon content is high, the solution treatment temperature must be increased or the heat treatment time must be prolonged to sufficiently dissolve the carbide. When the amount of the carbide is large, the carbide can be eliminated by solution treatment, but the compactness of the metal microstructure cannot be ensured. The super-microscopic defects exist in the austenite after the carbide is dissolved due to the difference between the specific volume of the carbide and the specific volume of the austenite. Thus, the higher the carbon content, the higher the number of carbides, the less dense the metal after heat treatment, and the lower the toughness.

The relationship between carbon content and strength and plasticity properties is related to the interaction of carbon as solute atoms and dislocations. The carbon atom radius is smaller than the radius of the iron and manganese atoms, so it must be concentrated in the compressive stress region around the dislocations, constituting a kosher gas cluster. The interaction between the carbon atoms and the dislocations increases the resistance to dislocation motion. Manifested by an increase in strength properties and a somewhat reduced plasticity.

Under the working condition of abrasion of the non-strong impact grinding material, the improvement of the carbon content is beneficial to improving the abrasion resistance of the steel. This is because a part of the carbides dispersed in the steel easily remain even by the solid solution strengthening action of carbon, that is, by the conventional solid solution treatment. This is a texture that is beneficial for improving wear resistance in non-high impact abrasive wear conditions. Such carbides also tend to occur when the carbon content in the steel is high and the manganese content is low.

Under the condition of strong impact, the carbon content is generally expected to be properly reduced to about 0.9-1.05% (the manganese content is not changed). The single-phase austenite structure can be obtained through heat treatment, has good plasticity and toughness, and is easy to strengthen in the deformation process. The original hardness of the material with low carbon content after solution treatment is HB 170-210. After the material is used, the material can be improved to HB 450-480. The depth of the hardened layer can reach 18 mm.

According to the above analysis, the carbon content is high, which can improve the hardness and the wear resistance, but the strength, the plasticity and the toughness of the steel are reduced, so the carbon content of the ultra-high manganese alloy steel is selected as follows: 1.0 to 1.4 percent.

Basic chemical composition manganese

The impact toughness is improved by increasing the manganese content. This is related to the effect of manganese in increasing intercrystalline bonding forces. The impact toughness at low temperatures is more strongly influenced by manganese, i.e. the impact toughness at low temperatures increases more rapidly with increasing manganese content.

Manganese is an element that promotes rapid growth of austenite dendrites. In the thin-wall casting, the thermal conductivity of the metal is reduced due to the high temperature gradient (which refers to the temperature gradient in the metal of the casting wall) and the manganese content, so that a transgranular structure is more easily obtained.

Manganese has an effect on the work-hardening capacity of the steel. When the carbon content is not changed, the manganese content increases and the work hardening ability improves.

Based on the above analysis, it was found that the best wear resistance of the steel can be achieved at a content of 18% in combination with the study of the document (11). Therefore, the manganese content of the ultra-high manganese alloy steel is selected as follows: 17-19%.

③ harmful element-phosphorus

Phosphorus is a harmful element in high manganese steels. Although the content of the phosphorus in the steel is far less than the contents of manganese and carbon, the phosphorus has important influence on the mechanical property, the wear resistance and the processing property of the steel. Phosphorus has little solubility in austenite. When the content of the phosphorus is high, the phosphorus is precipitated in the form of phosphide and phosphorus eutectic. Since the eutectic composition has a low melting point, it is inevitably distributed between dendrites when the crystal is solidified, and there is an initial grain boundary. The phosphorus eutectic is a brittle structure and inevitably has adverse effects on the normal temperature mechanical properties of the steel.

The impact of phosphorus on the impact toughness of high manganese steels is very significant. When the phosphorus content is increased by 0.01%, the impact toughness at normal temperature is reduced by 49-58.8J/cm². The increase in phosphorus reduces the strength, elongation and reduction of area and the magnitude of the reduction is approximately the same.

Phosphorus is easily segregated in high manganese steels, exacerbating the deleterious effects of phosphorus. When the content of the phosphorus is high, the segregation degree of other elements such as carbon and manganese is also increased. Considering the factors of raw materials and the like. The phosphorus content of the ultrahigh manganese alloy steel is selected as follows: less than 0.05%.

Conventional element-silicon

Silicon is soluble in austenite in high manganese steel and acts as a solid solution strengthening effect. While silicon changes the solubility of carbon in austenite. The influence of silicon on the mechanical and wear properties of steel is complex. Silicon is dissolved in austenite to affect the solubility of carbon in austenite, promote the desolventization of carbon, and precipitate as carbide. The increase of the silicon content not only causes the precipitation of carbide along the grain boundary but also increases the precipitation amount of carbide in the crystal, and the silicon has the function of changing the appearance of the carbide. When the silicon content is small, the carbide takes the shape of a needle sheet. When the silicon content increased to 0.8%, the carbides were lumpy.

The silicon content is high and the amount of as-cast carbide is inevitably large, which causes difficulty in heat treatment, and prolongs the heat treatment time or increases the heat treatment temperature, so that the crystal grains become coarse. Due to the increase in temperature, the metal surface is severely decarburized and even oxidized along grain boundaries within the surface layer. Silicon promotes the increase of carbides in the as-cast structure, which deteriorates the performance of the steel at high temperatures and becomes brittle at low temperatures. When the silicon content is 0.15%, carbide precipitates at grain boundaries and the impact toughness is lowered. For example, high silicon content in high manganese steel causes carbide decomposition, reduces the concentration of carbon in austenite, deteriorates the deformation strength capability, and increases the tendency of the casting to crack.

With reference to ZGMn13 and document (12), the silicon content of the ultra-high manganese alloy steel is selected as: 0.3 to 1.0 percent.

Sulfur as a harmful element

The high manganese steel contains a large amount of manganese, and most of sulfur and manganese are combined into manganese sulfide with a high melting point. Most of the products enter the slag, and the residual sulfur content in the steel is very low. Most of the forms of the residual manganese sulfide inclusions in the steel are close to spherical, and the influence on the performance of the steel is not great.

Therefore, the sulphur content of the ultra-high manganese alloy steel is selected as: less than 0.05%.

Aluminium as trace element

The aluminum in the high manganese steel is added as a deoxidizer, the adding amount is less, generally 0.06-0.15%, and a generated deoxidized product Al2O3 is obtained. Because oxides such as MnO, FeO, SiO2 and the like exist in the steel, Al2O3 and inclusions with lower melting point and smaller specific gravity are easily combined between the oxides. Alumina is difficult to play a role in refining the structure when the steel is crystallized, and is one of the causes of coarsening of the crystal structure of high manganese steel.

Aluminum has a stronger deoxidizing power than manganese. However, in steels with high manganese contents, its deoxidizing capacity will be impaired by the action of the law of mass action. Addition of too much aluminum does not enhance deoxidation and has an adverse effect. The aluminum content can be increased appropriately when the phosphorus content in the steel is high to reduce the detrimental effects of phosphorus.

Therefore, the aluminum content of the ultra-high manganese alloy steel is selected as: is less than 0.2 percent.

Seventhly, trace element-titanium

Titanium is added as ferrovanadium pig iron during smelting. Titanium forms mainly carbide elements, carbide and austenite have the same lattice type, i.e., face-centered cubic lattice, and a coherent relationship exists at austenite-carbide grain boundaries, i.e., the lattices are firmly connected together, so that the carbide is prevented from being peeled off during wear, and its high microhardness is also very effective against abrasive grain erosion wear. Titanium plays an important role in improving the quality of high manganese steel. Titanium can play a role in refining grains, and titanium can increase the stability of austenite when dissolved in steel. The following functions can be realized in the high manganese steel: refining crystal structure, eliminating columnar crystal, and improving mechanical properties and wear resistance.

Therefore, the titanium content of the ultra-high manganese alloy steel is selected as follows: is less than 0.2 percent.

Vanadium as trace element

After adding vanadium, the steel can be treated by water toughening, so that the vanadium is dissolved in austenite in a solid state, and the wear resistance of the steel can be improved. The addition of vanadium can also be followed by precipitation-enhanced treatments, which is an effective way to improve wear resistance.

Vanadium is one of the elements forming strong carbide, and vanadium-containing compounds have high melting points and can be used as a crystallization core during crystallization to refine casting structures. After vanadium is added, carbides in an as-cast structure are more dispersed, more in quantity and smaller in size.

In general, after vanadium is added to steel, the plasticity of the steel is reduced, the yield strength is improved, the hardness is improved, and the impact toughness is reduced. However, vanadium has an effect of significantly refining the crystal structure, and this adverse effect can be compensated for.

Thus, the vanadium content of the ultra-high manganese alloy steel is selected as: is less than 0.5 percent.

Ninthly alloy element-chromium

Chromium is the most widely used alloying element in alloying high manganese steels at home and abroad. The chromium content in the steel is increased, the hardenability of the steel is improved, and the hardness of the whole cast section is more uniform. The wear resistance of the steel is improved after the chromium is added.

The chromium content in high manganese steels is low, generally not exceeding 4%. Most of the chromium in the high manganese steel after the water toughening treatment is dissolved in austenite. The diffusion speed of chromium in iron is slow, and the interaction of chromium atoms reduces the diffusion speed of carbon, so that the stability of austenite is improved. This has an effect on the heat treatment of the chromium-containing high manganese steel structure.

1) Influence of chromium on the microstructure of high manganese steels

Chromium in high manganese steels changes the as-cast structure and the austenitic isothermal transformation curve of the steel. The amount of carbides in the as-cast structure of the steel generally increases with increasing chromium content. After the chromium is added, due to the characteristics of the diffusion process of the chromium and the influence of the chromium on the carbon diffusion process, the stability of austenite is improved, eutectoid transformation is late, and the single-phase austenite is difficult to obtain, so that the required assembly can be obtained only by increasing the temperature of solution treatment by 30-50 ℃.

2) Influence of chromium on mechanical Properties

Chromium, when dissolved in austenite, increases the yield strength of the steel, but decreases the elongation. When the chromium content is small, the tensile strength does not change much, and when the chromium content is high, the tensile strength decreases. The chromium content in the steel is increased at normal temperature, and the impact toughness is reduced. Chromium has an effect on the work-hardening capacity of high manganese steels, and the hardness value of chromium containing manganese steels increases higher than that of chromium free steels under the same deformation conditions.

As chromium has great influence on the work hardening capacity of manganese steel, and does not increase too much carbide, the chromium content of the ultrahigh manganese alloy steel is selected as follows: 1.5 to 2.5 percent.

Mechanical property of ultra-high manganese alloy steel ZGMn17Cr2

σb/MPa	σ0.2/MPa	δ(％)	ψ(％)	HBS	akv(J/cm2)
						≥750	≥430	≥30	≥30	220～240	≥100

Preferably, the main chemical components of the feeding end lining plate and the dustpan lining plate are shown as follows

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.