阅读说明：本技术 一种隧道掘进机刀箱内刀座板材料及其制备方法和刀箱 (Tool apron material in tunnel boring machine tool box, preparation method thereof and tool box ) 是由 张凌 戈强 马文超 张爱武 王艺蓓 方亮 于 2020-04-08 设计创作，主要内容包括：本发明涉及一种隧道掘进机刀箱内刀座板材料及其制备方法和刀箱,本发明的内刀座板材料的化学成分含量范围如下：C：0.38--0.45％,Si：0.50--0.70％,Mn：0.70--1.20％,P：＜0.010％,S：＜0.005％,Cr：0.90--1.20％,Mo：0.25--0.40％,Ce：0.15--0.25％,La：0.15--0.25％,余量：Fe。本发明的内刀座板材料的制备方法通过对元素成分的调整与电渣重熔精炼工艺的应用,生产出了具有硬度高、强度高、可淬性好,冲击韧性优良等特点的新型内刀座板材料XT-DZ。该材料经过锻造和性能热处理后,其Rm≥1450MPa,最终调质后的表面硬度50～55HRC。本发明的刀箱通过将现有的旧型刀箱设计中刀座单元内外刀座板之间的焊接固定结构改成新型的楔装机械式固定结构,完全避免了异种钢焊接固有的各类不利影响。(The invention relates to a material of an inner cutter seat plate of a tunnel boring machine cutter box, a preparation method thereof and the cutter box, wherein the material of the inner cutter seat plate comprises the following chemical components of 0.38-0.45% of C, 0.50-0.70% of Si, 0.70-1.20% of Mn, less than 0.010% of P, less than 0.005% of S, 0.90-1.20% of Cr, 0.25-0.40% of Mo, 0.15-0.25% of Ce, 0.15-0.25% of L a and the balance Fe..)

1. The cutter holder plate material in the cutter box of the tunnel boring machine is characterized by comprising the following chemical components in percentage by weight:

0.38 to 0.45 percent of C, 0.50 to 0.70 percent of Si, 0.70 to 1.20 percent of Mn, less than 0.010 percent of P, less than 0.005 percent of S, 0.90 to 1.20 percent of Cr, 0.25 to 0.40 percent of Mo, 0.15 to 0.25 percent of Ce, 0.15 to 0.25 percent of L a, and the balance of Fe.

2. The blade holder plate material in the tunnel boring machine blade box according to claim 1, characterized in that it comprises the following chemical components in percentage by weight:

0.39 percent of C, 0.50 percent of Si, 0.80 percent of Mn, less than 0.005 percent of P, less than 0.002 percent of S, 0.95 percent of Cr, 0.25 percent of Mo, 0.15 percent of Ce, 0.15 percent of L a, and the balance of Fe.

3. The blade holder plate material in the tunnel boring machine blade box according to claim 1, characterized in that it comprises the following chemical components in percentage by weight:

0.44 percent of C, 0.70 percent of Si, 1.18 percent of Mn, less than 0.008 percent of P, less than 0.004 percent of S, 1.15 percent of Cr, 0.39 percent of Mo, 0.25 percent of Ce, 0.25 percent of L a and the balance of Fe.

4. The blade holder plate material in the tunnel boring machine blade box according to claim 1, characterized by comprising, in weight percent:

0.42 percent of C, 0.60 percent of Si, 1.00 percent of Mn, less than 0.006 percent of P, less than 0.003 percent of S, 1.05 percent of Cr, 0.32 percent of Mo, 0.20 percent of Ce, 0.20 percent of L a, and the balance of Fe.

5. A method of manufacturing a blade holder plate material in a tunnel boring machine blade case according to any one of claims 1 to 4, comprising the steps of:

preparing one ton of waste 42CrMo steel, putting the waste 42CrMo steel into an intermediate frequency furnace, adding high-carbon ferrochrome and ferromolybdenum, melting the steel to eight hundred kilograms, carrying out stokehole analysis to obtain chemical components of tapping, adding the rest waste steel into the furnace, adding high-carbon ferromanganese when the furnace temperature reaches 1600-1650 ℃, adding ferrosilicon after one minute, pouring molten steel when the furnace temperature reaches 1650-1680 ℃, adding rare earth ceralloy and required aluminum wires according to the quantity of the molten steel, pouring the molten steel into a ladle, starting casting, casting the molten steel into a molten steel mold, cooling for twelve hours to sixteen hours, opening the mold, and pouring an XT-DZ steel rod; smelting a consumable electrode bar by using a vacuum medium-frequency induction furnace, finishing the surface of the consumable electrode bar to remove surface oxide skin and other impurities, performing electroslag remelting by using a vacuum electroslag furnace, and ensuring the purity and lower impurity content of molten steel to be smelted by using an electroslag refining process; in the refining process in the later smelting period, the slag is removed and formed for many times to improve the purity of the molten steel; final deoxidation treatment is required in the tapping process; the content of harmful element phosphorus P is less than 0.01 percent, and the content of sulfur S is less than 0.005 percent; the novel inner cutter seat plate material with high hardness, high strength, good hardenability and excellent impact toughness is obtained.

6. A knife box is characterized by comprising a pair of knife holder units which are mirror-symmetrical left and right;

each of the blade holder units includes: a first inner cutter saddle plate (1), a first outer cutter saddle plate (2) and 2 wedges (3);

the first inner cutter saddle plate (1) is fixed on the first outer cutter saddle plate (2), and the first inner cutter saddle plate (1) is pressed on the first outer cutter saddle plate (2) by using 2 wedges (3);

the material of the inner cutter seat plate (1) is the material of the inner cutter seat plate of the tunnel boring machine cutter box of any one of claims 1-4.

7. The knife box according to claim 6, characterized in that the first inner knife holder plate (1), the first outer knife holder plate (2) and the 2 wedges (3) are fixed by bolts.

8. The knife box according to claim 7, characterized in that the first inner knife holder plate (1) is provided with 8 screw holes and the first outer knife holder plate (2) is provided with 8 screw holes adapted to the first inner knife holder plate; each wedge block (3) is provided with 3 screw holes, and the first outer cutter seat plate (2) is provided with 6 screw holes corresponding to the first outer cutter seat plate; the first inner cutter seat plate (1) is fixedly positioned on the first outer cutter seat plate (2) through screw holes by 8 bolts, and the first inner cutter seat plate (1) is pressed on the first outer cutter seat plate (2) through the other 6 bolts through the screw holes in the 2 wedge blocks (3).

Technical Field

The invention relates to a novel material, in particular to a cutter holder plate material in a cutter box of a tunnel boring machine, a preparation method of the cutter holder plate material and the cutter box.

Background

The cutter box is a carrier for bearing connection between a hob of the tunnel boring machine and a cutter head of the tunnel boring machine. According to the rock breaking mechanism of the hob, in the rock breaking process of the hob, the generated large impact and vibration acting force is transmitted to the cutter box through parts such as a cutter shaft, an end cover, a support or a fixture block of the hob and then transmitted to a cutter head of the heading machine through the cutter box. Therefore, in the comprehensive stress structure of the heading machine cutterhead, the cutter box and the hob, the cutter box plays a key role, and whether the strength and the stable rigidity level of the cutter box meet the requirements or not directly influences whether the tail end (hob) of the system can work normally or not.

A typical single-edged hob case consists of a pair of (2) holder units, which are mirror-symmetrical with respect to each other. According to the existing design structure at present, a single-side tool apron unit comprises an outer tool apron plate 12 (made of carbon structural steel, such as Q345) and an inner tool apron plate 11 (made of high-strength alloy quenched and tempered steel forging, such as 42 CrMo). The two are firmly connected by welding, and the welder belongs to typical dissimilar steel welding, as shown in fig. 1.

The reason why the typical holder unit design (welded structure) shown in fig. 1 must be divided into the outer holder plate 12 and the inner holder plate 11 of different materials is that: the inner cutter saddle plate 11 is required to have high strength and high wear resistance (the surface has high hardness) in performance, so that high-strength alloy quenched and tempered steel such as 42CrMo and the like is selected for manufacturing; the outer cutter base plate 12 has basic strength performance, and also has excellent welding manufacturability of direct welding without preheating with a cutter head main body structure (a carbon structural steel welding structure) under the condition of a site assembly station of a cutter head of the tunneling machine, so that carbon structural steel materials are selected; therefore, the inner cutter base plate 11 and the outer cutter base plate 12 need to be assembled and welded in a factory (the dissimilar steel welding process of the inner cutter base plate and the outer cutter base plate needs to be preheated and post-heated), when the cutter head is assembled on site, the outer cutter base plate 12 can be directly cold-welded with the cutter head of the tunneling machine, and the quality of welding seams welded by the same material among the carbon structural steels is easily guaranteed. In conclusion, the practical function of the outer cutter base plate 12 is equivalent to serving as a welding transition backing plate and bearing bracket between the inner cutter base plate 11 and the cutter head main body structure.

In the typical tool apron unit design structure (welding structure) shown in fig. 1, in order to ensure that dissimilar steels of the inner tool apron plate 11 and the outer tool apron plate 12 are welded sufficiently and firmly, all the sections of the welding seams 13 must have sufficient strength, so that the welding groove between the inner tool apron plate 11 and the outer tool apron plate 12 is designed to be wide and deep; meanwhile, due to the technical characteristics of dissimilar steel welding, the following problems easily occur in the welding process:

a) welding residual deformation: the welding process is a dynamic process of local gradual rapid heating and cooling of a weld pool, and internal stress after welding is generated due to changes of overall shape and size, incongruity of deformation and mutual constraint of deformation and shrinkage caused by continuous local expansion and shrinkage. Due to the structural shape characteristics of the inner and outer cutter boxes, the restraint effect is strong in the welding process under the thermal expansion state, and the influence caused by dissimilar steel welding (material linear expansion coefficient difference) is added, so that the welding residual deformation of the inner cutter seat plate 11 and the outer cutter seat plate 12 is difficult to control, the deformation of a plurality of millimeters is usually caused by gradual release of post-welding stress, therefore, a process route of reserving allowance before welding and performing finish machining after welding has to be adopted, and the whole manufacturing efficiency is difficult to improve.

b) Weld joint defects such as cracks, inclusions, lack of fusion, flash, internal/external porosity, undercuts, and the like. Due to the fact that the welding characteristics of materials on two sides of the welding seam are different, the probability of defects of dissimilar steel welding is high.

c) Welding cracks: due to the constraint influence of the weldment structure, the residual stress in the welded workpiece is large, as shown in fig. 1, local stress concentration is naturally easy to occur at the root of each welding seam 13 (which is formed on a single surface), the defects existing at the root are more easily used as crack expansion sources under the action of concentrated stress, and penetrating crack defects are generated in serious cases, so that the welding seams 13 cannot pass through nondestructive detection and need to be reworked.

The design (welded structure and material selection) of the typical blade holder unit shown in fig. 1 has the following disadvantages in addition to the disadvantages caused by the above welding reasons:

(1) the field replacement and disassembly are troublesome. According to the structural design of the existing tool apron, the tool box is replaced in a tunnel on site, the inner tool apron plate 11 of each damaged tool apron unit is removed from the outer tool apron plate 12 in a carbon arc gouging mode, because the welding amount of the inner tool apron plate 11 and the outer tool apron plate 12 is large and the welding bead is deep, one inner tool apron plate 11 is planed out, about 4-5 hours are needed, tool aprons on two sides of one tool box are always required to be detached and replaced, and the total time is 8-10 hours; after the inner cutter seat plate 11 is planed, the residual burrs at the cutting position are required to be smoothly ground, polished and cleaned, the field space is narrow, the operation is difficult, and the operation needs hours; after that, a new inner cutter saddle plate 11 can be installed in place, and approximately 1-2 hours are needed; after the novel inner cutter saddle plate 11 and the original outer cutter saddle plate 12 are installed in place, the welding needs preheating (otherwise, cold cracks are easy to occur), the field process is difficult to implement, 6-7 hours are needed for approximately completing the welding, and 12-14 hours are needed for properly welding the two inner cutter saddle plates 11 of one set of cutter box. In summary, the replacement of a set of tool boxes in the tunnel on site needs 22 to 25 hours in total (which is the ideal working speed and certainly slower), and the more major problems are that: the welding one-time qualification rate is low, and the rework probability is very high. Because site operation conditions (environmental factors, personnel endurance and the like) are far inferior to factory conditions, various inherent defect risks of dissimilar steel welding problems are undoubtedly easier to occur, the overall efficiency is lower, and the quality of the welding seam 13 is more difficult to guarantee.

(2) The durability of the inner cutter plate 11 is not satisfactory. The raw tool apron is made of 42CrMo, and the hardness after quenching and tempering is as follows: 28-32 HRC, but the cutter box is required to have high hardness, strength and impact resistance (toughness) because of bearing severe and frequent alternating load in the rock breaking process of the tunneling machine, the hardness requirement of a working surface is 50-55 HRC, and the process is realized by local surface high-frequency quenching. The local surface high-frequency quenching process can better ensure the hardness index of a working surface when leaving a factory, but the depth of a hardening layer is relatively insufficient (the long-term wear resistance is not as good as that of a hardening layer obtained by conventional integral quenching, and the hardening depth of the hardening layer is higher than that of the hardening layer), and the quality of the hardening layer is often not stable enough actually. However, with the prior art welded tool holder design (as shown in fig. 1), it is not possible to apply the entire work piece temper (quench + high temperature temper) hardening process to the inner tool holder plate 11 because: residual deformation is bound to exist in the welding of the inner and outer cutter holder plates 11 and 12, and each working surface (with higher requirements on size and form and position precision) must be subjected to finish milling after welding, so that the whole quenching and tempering hardening process of the inner cutter holder plate 11 is not feasible on a process route, and in addition, the whole quenching and tempering treatment of the finished cutter holder unit is not possible, so that a local surface high-frequency quenching process can be applied to the working surface only after the finish machining; the limitations caused by the inherent contradiction make the durability of the inner cutter seat plate 11 difficult to reach the theoretical performance limit of the material itself.

Disclosure of Invention

The invention provides a cutter holder plate material in a cutter box of a tunnel boring machine, a preparation method thereof and the cutter box, aiming at solving the technical problems in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the invention provides a cutter seat plate material in a cutter box of a tunnel boring machine, which comprises the following chemical components in percentage by weight:

0.38 to 0.45 percent of C, 0.50 to 0.70 percent of Si, 0.70 to 1.20 percent of Mn, less than 0.010 percent of P, less than 0.005 percent of S, 0.90 to 1.20 percent of Cr, 0.25 to 0.40 percent of Mo, 0.15 to 0.25 percent of Ce, 0.15 to 0.25 percent of L a, and the balance of Fe.

In the above technical solution, it is preferable that: the cutter holder plate material in the tunnel boring machine cutter box comprises the following chemical components in percentage by weight:

0.39 percent of C, 0.50 percent of Si, 0.80 percent of Mn, less than 0.005 percent of P, less than 0.002 percent of S, 0.95 percent of Cr, 0.25 percent of Mo, 0.15 percent of Ce, 0.15 percent of L a, and the balance of Fe.

In the technical scheme, the preferable material of the tool apron plate in the tunnel boring machine tool box comprises, by weight, 0.44% of C, 0.70% of Si, 1.18% of Mn, less than 0.008% of P, less than 0.004% of S, 1.15% of Cr, 0.39% of Mo, 0.25% of Ce, 0.25% of L a and the balance Fe.

In the above technical solution, it is preferable that: the cutter holder plate material in the tunnel boring machine cutter box comprises the following chemical components in percentage by weight:

0.42 percent of C, 0.60 percent of Si, 1.00 percent of Mn, less than 0.006 percent of P, less than 0.003 percent of S, 1.05 percent of Cr, 0.32 percent of Mo, 0.20 percent of Ce, 0.20 percent of L a, and the balance of Fe.

The invention also provides a preparation method of the tool apron plate material in the tool box of the tunnel boring machine, which comprises the following steps:

the method comprises the steps of preparing a steel material of 42CrMo, putting one ton of the steel material into an intermediate frequency furnace, adding high-carbon ferrochrome (Cr percent is more than or equal to 57 percent) and ferromolybdenum (Mo percent is more than or equal to 60.17 percent) to melt to about eight hundred kilograms, carrying out analysis before the furnace to obtain chemical components of tapping, adding the rest steel scrap into the furnace, adding high-carbon ferromanganese (Mn is more than or equal to 65 percent) when the furnace temperature reaches 1600-1650 ℃, adding ferrosilicon (Si percent is more than or equal to 75.12 percent) after one minute, pouring molten steel when the furnace temperature reaches 1650-1680 ℃, adding rare earth cerium lanthanum alloy (Ce is more than or equal to 45 percent and L a is more than or equal to 17 percent) and required aluminum wires according to the quantity of the molten steel, pouring the molten steel into a ladle, casting the molten steel into a molten steel mold, opening the mold to pour out a steel rod after cooling for twelve hours to sixteen hours, smelting out the self-consuming electrode rod by using a vacuum intermediate frequency induction furnace to smelt the self consuming pure steel rod, finishing the surface of the self consuming electrode rod, removing surface oxide skin and impurities, remelting, ensuring that the content of the pure slag is less than 0.005 percent and the slag is less than 0.005, and the slag is good in the smelting process of the slag in the high-smelting process of the high-smelting, and the high-slag, and the slag is good in the late stage of smelting process of smelting, and the high-slag, and the high.

The invention also provides a knife box which is composed of a pair of knife holder units with mirror symmetry left and right;

each of the blade holder units includes: a first inner cutter saddle plate, a first outer cutter saddle plate and 2 wedges;

the first inner cutter seat plate is fixed on the first outer cutter seat plate, and the first inner cutter seat plate is pressed on the first outer cutter seat plate by using 2 wedges;

the material of the inner cutter saddle plate is the material of the inner cutter saddle plate.

In the above technical solution, the first inner cutter seat plate, the first outer cutter seat plate and the 2 wedges are fixed by bolts.

In the above technical solution, the first inner cutter seat plate is provided with 8 screw holes, and the first outer cutter seat plate is provided with 8 screw holes adapted to the first inner cutter seat plate; each wedge block is provided with 3 screw holes, and the first outer cutter seat plate is provided with 6 screw holes matched with the first outer cutter seat plate; the first inner cutter seat plate is fixedly positioned on the first outer cutter seat plate through screw holes by 8 bolts, and then the first inner cutter seat plate is pressed on the first outer cutter seat plate through the screw holes on 2 wedge blocks by other 6 bolts.

The invention has the beneficial effects that:

according to the material for the cutter holder plate in the tunnel boring machine cutter box, on the basis of the original 42CrMo material, a proper amount of Si, Mn, Mo and rare earth elements Ce and L a are added, the production process of smelting is strictly controlled, the surface hardening process of the inner cutter holder plate is changed into the integral hardening and tempering of the inner cutter holder plate (because the inner cutter holder plate and the outer cutter holder plate do not need to be welded, all problems caused by welding are avoided), and a novel material XT-DZ. for the inner cutter holder plate is obtained, and has high hardness, high wear resistance and good impact toughness.

The blade holder plate material in the tunnel boring machine tool box is characterized in that on the basis of the original 42CrMo brand component, the content of silicon and manganese is properly improved to improve the impact toughness, the content of molybdenum is properly improved to refine structure grains, improve the strength, the hardenability and the tempering stability, a certain amount of rare earth elements Ce and L a are supplemented to improve the hardenability and other properties on the basis of keeping the carbon content of the material unchanged, and the content of non-metal inclusions and the content of harmful elements such as phosphorus, sulfur and oxygen are reduced to the maximum extent in the smelting process.

The preparation method of the tool apron plate material in the tunnel boring machine tool box of the invention produces the novel inner tool apron plate material XT-DZ with the characteristics of high hardness, high strength, good hardenability, excellent impact toughness and the like by adjusting the element components and applying the electroslag remelting refining process. After forging and performance heat treatment, Rm of the material is more than or equal to 1450MPa, and the surface hardness of the material after final quenching and tempering is 50-55 HRC.

According to the tool box, the material XT-DZ is used as the material of the inner tool apron plate, and the welding fixing structure between the inner tool apron plate and the outer tool apron plate of the tool apron unit in the existing old tool box design is changed into a novel wedge-mounted mechanical fixing structure, so that various inherent adverse effects of dissimilar steel welding, such as the problem of welding residual stress deformation, the problem of possible defects and high rework rate of a welding seam, the problem of complex process route and the like, are completely avoided, the process route is greatly simplified, the one-time qualification rate of a product is greatly improved, the comprehensive production cost of a tool box production enterprise is remarkably reduced, and the application threshold is very low, so that the tool box is suitable for large-scale popularization and application in the industry.

The tool box changes the welding fixing structure between the inner tool apron plate and the outer tool apron plate of the tool apron unit in the existing old tool box design into a novel wedge-mounted mechanical fixing structure, so that the selection of materials and the formulation of a process route of the inner tool apron plate completely do not need to consider the factors such as the weldability, the welding defects and the like of the materials, and only needs to directly consider how to optimize the service performance: strength (influence of material components), hardness (influence of material components and quenching heat treatment process), continuous wear resistance (thickness of a hardened layer, influence of hardenability of the material and quenching heat treatment process), impact toughness (mainly influence of material components), and difficulty in optimizing and improving and applying the material per se is reduced. The invention obtains a novel modified material XT-DZ by optimizing the components and the process of the material of the inner cutter base plate, combines the application of an electroslag refining remelting process and the integral quenching and tempering heat treatment of the inner cutter base plate (the application of the hardening process benefits from the structural improvement provided by the invention, the original cutter base welding structure can only adopt a local high-frequency quenching mode for hardening, the thickness of the quenched layer, the quality stability of the quenched layer and the like are obviously inferior to the effect achieved by the integral quenching and tempering heat treatment process), and the improvement obviously improves the service performance of the inner cutter base plate.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Fig. 1 is a schematic view of a typical conventional tool holder unit structure (welded structure).

Fig. 2 is a schematic view of an improved novel tool apron unit structure (wedge-type structure).

Fig. 3 is a schematic structural view of a second inner cutter holder plate according to the present invention.

Fig. 4 is a schematic structural view of a second outer cutter holder plate according to the present invention.

Fig. 5 is a schematic structural view of the wedge of the present invention.

The reference numerals in the figures denote:

11-inner cutter seat plate, 12-outer cutter seat plate and 13-welding line;

1-a first inner cutter seat plate, 2-a first outer cutter seat plate and 3-a wedge block;

Detailed Description

The invention has the thought that on the basis of the original 42CrMo material components, a proper amount of Si, Mn, Mo and rare earth Ce, L a are added, the production process of smelting is strictly controlled, meanwhile, the surface hardening process of the inner cutter seat plate is changed into the integral tempering of the inner cutter seat plate (because the inner cutter seat plate and the outer cutter seat plate do not need to be welded, all problems caused by welding are avoided), a new inner cutter seat plate XT-DZ. is obtained, the material has high hardness, high wear resistance and good impact toughness, the content of silicon and manganese is properly improved (the impact toughness is improved) on the basis of the original 42CrMo brand components, the content of molybdenum is properly improved (the structure crystal grains are refined, the strength, the hardenability and the tempering stability are improved), a certain amount of rare earth elements are supplemented (the hardenability and the like are improved) on the basis of keeping the carbon content of the material unchanged, and the content of non-metal inclusions and the content of harmful elements such as phosphorus, sulfur and oxygen are reduced to the greatest extent in the.

The invention provides a cutter seat plate material in a tunnel boring machine cutter box, which comprises the following chemical components in percentage by weight:

0.38 to 0.45 percent of C, 0.50 to 0.70 percent of Si, 0.70 to 1.20 percent of Mn, less than 0.010 percent of P, less than 0.005 percent of S, 0.90 to 1.20 percent of Cr, 0.25 to 0.40 percent of Mo, 0.15 to 0.25 percent of Ce, 0.15 to 0.25 percent of L a, and the balance of Fe.

It is preferable that: the cutter seat plate material in the cutter box of the tunnel boring machine comprises the chemical components and the weight percentage

0.39 percent of C, 0.50 percent of Si, 0.80 percent of Mn, less than 0.005 percent of P, less than 0.002 percent of S, 0.95 percent of Cr, 0.25 percent of Mo, 0.15 percent of Ce, 0.15 percent of L a, and the balance of Fe.

It is preferable that: the cutter seat plate material in the cutter box of the tunnel boring machine comprises the chemical components and the weight percentage

0.44 percent of C, 0.70 percent of Si, 1.18 percent of Mn, less than 0.008 percent of P, less than 0.004 percent of S, 1.15 percent of Cr, 0.39 percent of Mo, 0.25 percent of Ce, 0.25 percent of L a and the balance of Fe.

It is preferable that: the cutter seat plate material in the cutter box of the tunnel boring machine comprises the chemical components and the weight percentage

0.42 percent of C, 0.60 percent of Si, 1.00 percent of Mn, less than 0.006 percent of P, less than 0.003 percent of S, 1.05 percent of Cr, 0.32 percent of Mo, 0.20 percent of Ce, 0.20 percent of L a, and the balance of Fe.

In order to improve the purity of the material and thus the impact toughness, the following measures are taken in the smelting process of the material:

the invention provides a preparation method of a cutter holder plate material in a tunnel boring machine cutter box, which comprises the following steps:

the method comprises the steps of preparing a scrap 42CrMo steel, putting the steel into an intermediate frequency furnace, adding high-carbon ferrochrome (Cr% is more than or equal to 57%), ferromolybdenum (Mo) is more than or equal to 60.17%) to melt, melting to about eight hundred kilograms, carrying out analysis in front of the furnace to obtain chemical components of tapping, adding the rest scrap steel into the furnace, adding high-carbon ferromolybdenum (Mn is more than or equal to 65%) when the furnace temperature reaches 1600-1650 ℃, adding ferrosilicon (Si% is more than or equal to 75.12%) after one minute, pouring molten steel when the furnace temperature reaches 1650-1680 ℃, adding rare earth ceralloy (Ce is more than or equal to 45%, L a is more than or equal to 17%) and required aluminum wires according to the quantity of the molten steel, pouring the molten steel into a ladle, casting the molten steel into a molten steel mold, opening the mold to pour out a steel rod after cooling for twelve hours to sixteen hours, smelting out a self-consuming pure iron rod by using a vacuum intermediate frequency induction furnace, finishing the surface of the self-consuming electrode rod, removing surface oxide scale and other oxide inclusions, remelting by a vacuum furnace, remelting, and refining process, wherein the contents of the high-carbon-iron alloy are adjusted by adding high-smelting slag, the high-carbon slag, the high-smelting-carbon-smelting-lanthanum-iron alloy, the slag refining process is characterized in that the high-slag refining process that the high-slag has the contents of the high-smelting-slag is more than 0% of smelting-slag, the high-slag refining process of the high-slag, the high-slag refining process.

When the material that uses the interior tool apron and smelting technology itself improve, change the case hardening technology of interior tool apron into the whole quenching and tempering of work piece (because interior outer tool apron no longer need the welding, avoided because of all problems that the welding brought), make its physical properties have great improvement, embody: the surface hardness achieved after quenching and tempering is higher, the improved process enables the thickness of a surface hardening layer (the depth of quenching and tempering heat treatment) to be deeper, the hardening range to be larger (the surface of a whole workpiece is completely hardened), the wear resistance of a working surface to be more stable, and the service life of the workpiece to be obviously prolonged.

The improved tool box set comprises two improved tool apron units which are in mirror symmetry from left to right, wherein each improved tool apron unit comprises 1 outer tool apron plate, 1 inner tool apron plate, 2 wedge blocks and 14M 24 × 110-12.9 bolts, the improved inner tool apron plates are positioned and fixed on the outer tool apron plates by using 8 bolts, and the inner tool apron plates are pressed on the outer tool apron plates by using 2 wedge blocks by using the other 6 bolts, so that firm wedge-mounting and fixing are realized.

In practical use, the size of the novel tool apron unit can be designed in a targeted manner according to specific equipment requirements, and the locking force can be realized by adopting different locking wedges, locking bolts and other methods according to specific locking requirements, the wedge-mounted tool apron unit disclosed by the invention adopts 14 high-strength bolts of M24 × 110-12.9, the bolts meet the requirements of GB/T5782-2000, the pretightening force is not less than 230KN, and the tightening torque is not less than 1200 N.m.

The improved structure corresponds to the improved structure, greatly simplifies and improves the production flow of the tool apron unit, completely avoids the influence of welding operation and all relevant adverse factors, greatly improves the efficiency of each link of production, processing, assembly, field installation, maintenance and replacement, greatly shortens the construction period effectively and reduces the cost of each link.

The production process of the novel tool apron unit comprises the following steps:

the present invention is described in further detail below by way of specific examples.