阅读说明：本技术 一种高强韧性工程机械用钢板形控制方法 (High-strength and high-toughness steel plate shape control method for engineering machinery ) 是由 张继永 李俊生 李红俊 孙毅 李爱民 周建川 田文波 于 2021-08-13 设计创作，主要内容包括：一种高强韧性工程机械用钢板形控制方法,包括板坯加热、粗轧、精轧、控制冷却和轧后缓冷工序；控制冷却工序采用层流冷却工艺,水温20-32℃,层流冷却集管分为前段和后段,层冷系统中前段冷却集管中奇数组开启、偶数组关闭,形成分组间隔冷却模式；前段间隔冷却是对前10组进行分组间隔,当二级模型根据精轧出口温度预开启的前段奇数组集管数不够时,增开前10组奇数组中剩余集管及后段集管；增开的前段奇数组U型管冷却水开启顺序为由后向前,后段U型管冷却水开启顺序为由前向后,以改善层冷侧喷的吹扫效果。本发明生产的工程机械用带钢开平后不平度控制在5mm/m以内,纵切分条后侧弯量控制在8mm/通长以内。(A high-strength and high-toughness steel plate shape control method for engineering machinery comprises the working procedures of plate blank heating, rough rolling, finish rolling, controlled cooling and slow cooling after rolling; the control cooling process adopts a laminar cooling process, the water temperature is 20-32 ℃, the laminar cooling header is divided into a front section and a rear section, odd groups in the front section cooling header in the laminar cooling system are opened, and even groups in the front section cooling header are closed, so that a grouping interval cooling mode is formed; the front section interval cooling is to perform grouping interval on the front 10 groups, and when the number of front section odd-number groups of collecting pipes pre-opened by the secondary model according to the finish rolling outlet temperature is not enough, the rest collecting pipes and the rear section collecting pipes in the front 10 groups of odd-number groups are increased; the cooling water of the front section odd-number U-shaped pipes which are opened is opened from back to front, and the cooling water of the rear section U-shaped pipes is opened from front to back, so that the purging effect of the laminar cooling side spraying is improved. The unevenness of the band steel for the engineering machinery produced by the invention is controlled within 5mm/m after flattening, and the lateral bending amount is controlled within 8 mm/full length after slitting and slitting.)

1. A high-strength and high-toughness steel plate shape control method for engineering machinery comprises the working procedures of plate blank heating, rough rolling, finish rolling, controlled cooling and slow cooling after rolling; the method is characterized in that: in the control cooling process, a laminar cooling process is adopted, the laminar cooling header is divided into a front section and a rear section, and odd groups in the front section cooling header in the laminar cooling system are opened and even groups in the laminar cooling system are closed to form a grouped interval cooling mode; the front-section grouping interval cooling is to perform grouping interval on the front-10 groups, and when the number of front-section odd-number groups of collecting pipes pre-opened by the secondary model according to the finish rolling outlet temperature is not enough, the rest collecting pipes and the rear-section collecting pipes in the front-10 groups of odd-number groups are increased; the cooling water of the front section odd-number U-shaped pipes which are opened is opened from back to front, and the cooling water of the rear section U-shaped pipes is opened from front to back, so that the purging effect of the laminar cooling side spraying is improved.

2. The steel plate shape control method for the high-strength and high-toughness engineering machinery, which is disclosed by claim 1, is characterized in that the cooling process is controlled, wherein the cooling water temperature is 20-32 ℃; the cooling speed in the whole layer cooling process is 25-60 ℃/s, and the whole layer cooling process is cooled to 500-650 ℃ for coiling.

3. The steel plate shape control method for the high-strength and high-toughness engineering machinery, according to claim 1, is characterized in that: the finish rolling process adopts micro-medium wave rolling, the flatness correction value of a secondary model is-1 IU to-5 IU, and the finish rolling temperature is 830-.

4. The steel plate shape control method for high-strength high-toughness engineering machinery as claimed in claim 1 or 3, wherein: in the finish rolling procedure, the finish rolling inlet temperature is 900-.

5. The steel plate shape control method for the high-strength and high-toughness engineering machinery, according to claim 1, is characterized in that: and in the step of slow cooling after rolling, the steel coil is lifted into a finished product slow cooling warehouse within 10min after being off line, the steel coil is required to be stacked in the slow cooling warehouse in a centralized manner, and the steel coil is taken out of the warehouse after being slowly cooled for 24-72 h.

6. The steel plate shape control method for the high-strength and high-toughness engineering machinery, according to claim 1, is characterized in that: in the slab heating procedure, the heating furnace keeps reducing or neutral atmosphere during production, the air-fuel ratio is set to be 0.9-1.2, the slab discharging temperature is 1240-1300 ℃, the residence time in the soaking section of the heating furnace is 30-50min, and the total heating time is 160-350 min;

in the rough rolling procedure, 3+3 or 3+ 5 passes of rolling are adopted, the reduction rate of the last two passes is controlled to be between 20% and 30%, and the accumulated reduction rate of the rough rolling is controlled to be between 65% and 90%.

7. The steel plate shape control method for the high-strength and high-toughness engineering machinery, according to claim 1, is characterized in that: the high-strength and high-toughness steel for engineering machinery has the yield strength of over 800MPa, the elongation after fracture of not less than 18 percent and the low-temperature impact property of not less than 80J at minus 40 ℃.

8. The steel plate shape control method for the high-strength and high-toughness engineering machinery, according to claim 1, is characterized in that: the steel for the high-strength and high-toughness engineering machinery comprises the following chemical components in percentage by weight: 0.03-0.12% of C, 0.04-0.24% of Si, 1.40-2.00% of Mn, less than or equal to 0.018% of P, less than or equal to 0.005% of S, 0.005-0.048% of Als, Nb: 0.025% -0.055%, V: 0.05 to 0.12 percent of Ti, 0.070 to 0.15 percent of Ti, 0.0005 to 0.0050 percent of B, less than or equal to 0.0055 percent of N, and the balance of Fe and inevitable residual elements.

Technical Field

The invention relates to a high-strength and high-toughness steel plate shape control method for engineering machinery, and belongs to the technical field of metallurgical rolling.

Background

The steel for engineering machinery is widely applied to the fields of large-scale bearing structural parts, bulldozers, crane booms, pump trucks, excavators, mine car machinery, hydraulic supports and the like, and has special service environment and processing technology, and the steel is required to have high enough strength, good weldability and excellent low-temperature impact toughness. A part of steel for engineering machinery adopts a longitudinal cutting and slitting processing technology, and the requirements are that the plate surface is straight, the internal residual stress is small, and the shape of the original plate is harsh. In order to meet the quality requirements of high performance and high plate shape of steel for engineering machinery, most manufacturers add a large amount of expensive metals such as Mo, Cr, Ni and the like into the steel to improve the toughness of the steel, increase the alloy cost, and simultaneously carry out quenching and tempering heat treatment on the rolled steel plate to ensure the performance and the plate shape, the production process is complex, the process energy consumption is high, and the delivery cycle is generally longer.

The patent with the publication number of CN108531816B discloses '500 MPa grade steel for engineering machinery and a manufacturing method thereof', wherein the steel comprises the following components in percentage by mass: c: 0.12% -0.23%, Si: 0.10-0.60%, Mn: 0.80% -1.90%, P: < 0.018%, S: less than 0.010 percent; and is selected from Cr: 0-0.50%, Ni: 0-0.60%, Mo: 0-0.45%, Cu: 0-0.40%, Nb: 0 to 0.060%, V: 0-0.15%, Ti: 0-0.12%, B: 0-0.0030%, Al: 0.010-0.050%, and the balance of Fe and inevitable impurities. The patent relates to a manufacturing method, which adopts a post-rolling off-line heat treatment process, and firstly adopts a nitrogen protection non-oxidation roller hearth furnace to heat a steel plate to 880-920 ℃; then performing roll-pressing type water-jet quenching on the steel plate; and then the high-temperature tempering treatment is carried out at 550-660 ℃, so that the production process flow is long, and the energy consumption of the working procedure is high. The yield strength of the steel plate produced by the method is only 530 MPa and 556MPa, and the application of the steel plate on large-scale load-bearing parts is limited.

The patent with the publication number of CN111575609 discloses 'steel for engineering machinery with high strength, good plasticity and toughness and a preparation method thereof', the steel for engineering machinery comprises the following chemical components in percentage by mass: 0.075-0.085%, Si: 0.16-0.20%, Mn: 1.77% -1.84%, P: less than or equal to 0.015 percent, S: less than or equal to 0.005 percent, Cr: 0.25% -0.33%, Ni: 0.22-0.30%, Mo: 0.12% -0.18%, Nb: 0.028% -0.035%, Ti: 0.011% -0.018%, V: 0.036% -0.043%, B: 0.0009% -0.0015%, Al: 0.030 to 0.040 percent, and the balance of Fe and inevitable impurities. According to the method, a large amount of expensive alloy elements such as Cr, Mo and Ni are added for improving the hardenability of steel, an on-line quenching and low-temperature tempering process is adopted in the production process, the cooling temperature of finish rolling is at 830 +/-20 ℃, a martensite structure is obtained by on-line quenching after the finish rolling is rapidly cooled to 120-180 ℃, the residual stress of a steel plate is too large due to uneven cooling of the steel plate caused by rapid cooling, and the residual stress is difficult to completely eliminate even through low-temperature tempering treatment so as to ensure the plate shape quality of a finished product.

Patent No. CN110983204B discloses 'a steel plate for engineering machinery and a preparation method thereof'. According to the method, a continuous casting slab with the thickness of 300mm is used for producing a medium plate with the thickness of 100-110mm, and the product structure performance is guaranteed to meet the design requirement under the condition of low compression ratio through a controlled rolling and controlled cooling process and a rolled off-line tempering process. However, the steel of the patent relates to the engineering machinery, the process is complex, the delivery period is long, the tensile strength of the finished product is only 620-670MPa, the material strength is limited, and the steel is not suitable for being used on large and key bearing parts such as crane booms, hydraulic supports and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing a high-strength and high-toughness steel plate shape control method for engineering machinery, and meeting the special requirements of the field of steel for the engineering machinery on high plate shape quality.

The technical scheme for solving the technical problems is as follows:

a high-strength and high-toughness steel plate shape control method for engineering machinery comprises the working procedures of plate blank heating, rough rolling, finish rolling, controlled cooling and slow cooling after rolling;

the control cooling process adopts a laminar cooling process, the water temperature is 20-32 ℃, and a front-section interval cooling strategy is selected, namely, an odd number group of a front-section cooling header in a laminar cooling system is opened and an even number group of the front-section cooling header in the laminar cooling system is closed, so that a grouping interval cooling mode is formed; the laminar flow cooling collecting pipe is divided into a front section and a rear section, the front section interval cooling is to carry out grouping interval on the front 10 groups, and when the number of the collecting pipes of the front section odd-numbered groups pre-opened by the secondary model according to the finish rolling outlet temperature is not enough, the rest collecting pipes and the rear section collecting pipes in the front 10 groups of odd-numbered groups are increased; and simultaneously, optimizing the water outlet sequence of the collecting pipes, wherein each group of collecting pipes is respectively provided with 4/8/16U-shaped pipes, the opening sequence of the cooling water of the opened front section odd group of U-shaped pipes is from back to front, the opening sequence of the cooling water of the rear section U-shaped pipes is from front to back, so as to improve the purging effect of layer cold side spraying, the cooling speed in the whole layer cold process is 25-60 ℃/s, and the cooling is carried out to 500-650 ℃ for coiling.

In the finish rolling process, the steel plate shape control method for the high-strength and high-toughness engineering machinery adopts micro-medium wave rolling, the flatness correction value of a secondary model is-1 IU-5 IU, and the finish rolling temperature is 830-910 ℃.

In the finish rolling process, the finish rolling inlet temperature is 900-1000 ℃, the reduction rate of a final finish rolling frame is 8-12%, and the cumulative reduction rate of finish rolling is controlled according to 60-80%.

In the control method for the shape of the steel strip plate for the high-strength and high-toughness engineering machinery, in the step of slow cooling after rolling, the steel strip is hung into a finished product slow cooling warehouse within 10min after being off-line, and is required to be stacked in the slow cooling warehouse in a centralized manner, and is discharged after being slowly cooled for 24-72 h.

In the plate shape control method for the steel for the high-strength and high-toughness engineering machinery, in the plate blank heating process, the heating furnace keeps a reducing or neutral atmosphere during production, the air-fuel ratio is set to be 0.9-1.2, the plate blank discharging temperature is 1240-1300 ℃, the residence time in the soaking section of the heating furnace is 30-50min, and the total heating time is 160-350 min;

in the rough rolling procedure, 3+3 or 3+ 5 passes of rolling are adopted, the reduction rate of the last two passes is controlled to be between 20% and 30%, and the accumulated reduction rate of the rough rolling is controlled to be between 65% and 90%.

The steel plate shape control method for the high-strength and high-toughness engineering machinery comprises the following chemical components in percentage by weight: 0.03-0.12% of C, 0.04-0.24% of Si, 1.40-2.00% of Mn, less than or equal to 0.018% of P, less than or equal to 0.005% of S, 0.005-0.048% of Als, Nb: 0.025% -0.055%, V: 0.05 to 0.12 percent of Ti, 0.070 to 0.15 percent of Ti, 0.0005 to 0.0050 percent of B, less than or equal to 0.0055 percent of N, and the balance of Fe and inevitable residual elements.

According to the plate shape control method for the steel for the high-strength and high-toughness engineering machinery, the yield strength of the steel for the high-strength and high-toughness engineering machinery is over 800MPa, the elongation after fracture is not less than 18%, and the low-temperature impact property at minus 40 ℃ is not less than 80J.

The invention adopts a micro-moderate wave rolling strategy, a front section interval cooling mode and an optimized layer cooling water outlet sequence, so that the produced steel for the engineering machinery has good structure performance and good plate shape, and the main basis of the formulation of technological parameters is as follows:

the rolling adopts a micro-medium wave rolling strategy, the middle part of the strip steel is enabled to present a certain over-extension amount through the control of the shape of the finish rolling plate, namely, the finish rolling outlet is in a micro-medium wave state, the over-extension amount applied to the middle part just compensates the length difference between the edge part and the middle part caused by the temperature difference, and the purpose of controlling the wave shape or the longitudinal cutting lateral bending of the edge part of the final finished product is achieved. The secondary model flatness correction value is inversely related to the middle over-extension, and the larger the middle required over-extension, the smaller the flatness correction value is set. The flatness correction value of the secondary model is proper, if the flatness correction value is too large, the middle part is not enough in over-extension amount, and the length difference between the side part and the middle part caused by temperature difference cannot be compensated, so that the final finished product is subjected to edge wave; if the value is too small, the middle over-extension amount is too large and exceeds the required length compensation value of the edge part and the middle part, so that the final finished product has large middle waves. Based on the above consideration, it is preferable to control between-1 IU and-5 IU when setting the secondary model flatness correction value.

The control cooling process adopts a laminar cooling process, the water temperature is 20-32 ℃, and a front-section interval cooling strategy is selected, namely an odd-number group in a front-section cooling header in a laminar cooling system is opened and an even-number group in the front-section cooling header in the laminar cooling system is closed, so that a grouping interval cooling mode is formed; the laminar flow cooling collecting pipe is divided into a front section and a rear section, the front section interval cooling is to perform grouping interval on the front 10 groups, when the number of the collecting pipes of the front section odd-numbered groups which are pre-opened by the secondary model according to the finish rolling outlet temperature is not enough, for example, the actual coiling temperature is higher after pre-opening the collecting pipes of the 1 st, 3 th and 5 th groups, the rest collecting pipes in the front 10 groups of odd-numbered groups and the rear section collecting pipes are opened, for example, the cooling water of the 7 th and 9 th groups and the cooling water of the 11 th to 13 th groups are opened at the front section. And simultaneously, the water outlet sequence of the collecting pipes is optimized, each group of collecting pipes is respectively provided with 4/8/16U-shaped pipes, the opening sequence of the cooling water of the opened front section odd group of U-shaped pipes is from back to front, and the opening sequence of the cooling water of the rear section U-shaped pipes is from front to back, so that the purging effect of the layer cold side spraying is improved. The cooling speed in the whole layer cooling process is 25-60 ℃/s, and the whole layer cooling process is cooled to 500-650 ℃ for coiling.

The water temperature influences the cooling speed and the cooling efficiency of the strip steel, and needs to be controlled in a key way during cooling, and the water temperature is preferably controlled to be 20-32 ℃ in combination with the actual production. In order to obtain good structure performance, the cooling rate is required to be controlled at 25-60 ℃/s according to the CCT curve and the actual cooling capacity of the layer cooling equipment, and the final cooling temperature is controlled at 500-650 ℃ for coiling, so that the microalloy is favorably and fully precipitated.

The invention mainly bases on the design of components:

c: carbon is an efficient interstitial solid solution strengthening element, a certain amount of carbon is required to ensure the strength of the steel, but the welding performance and the toughness of the steel are influenced by the excessively high carbon content. Therefore, the C content is preferably controlled to 0.03% -0.12% in the present invention.

Si: silicon plays roles of deoxidation and solid solution strengthening in steel, but the content increases the brittleness of the steel, reduces the impact toughness and also affects the surface quality. Therefore, Si of the present invention is preferably controlled to 0.04% to 0.24%.

Mn: manganese plays a role in solid solution strengthening in steel, if the content of Mn is too low, the strength allowance of the steel is insufficient, more alloy elements are required to be added to improve the strength, but excessive Mn is easy to be separated and crystallized in the casting blank cooling process to form segregation, and a banded structure is formed in the genetic rolling process. The band-shaped structure destroys the uniformity of the structure and affects the plasticity and impact toughness of the steel. Therefore, the Mn in the present invention is preferably controlled to 1.40% to 2.00%.

P and S: the sulfur is taken as a harmful element in the steel, the purity and the structure property of the steel are influenced, the smelting process needs to be strictly controlled, and the sulfur is preferably controlled within 0.005 percent in combination with the cost. Phosphorus is a harmful element in steel, excessively high phosphorus can increase the ductile-brittle transition temperature of the steel and reduce the low-temperature impact property of the steel, and the phosphorus is strictly controlled within 0.018 percent in the invention to obtain the girder steel with excellent performance.

And Als: the aluminum plays a role in deoxidation in molten steel smelting, but too high Al can form large-size Al₂O₃And impurities are mixed, so that the low-temperature impact property of the steel plate is reduced. Therefore, the Al content in the present invention is preferably controlled to be between 0.005% and 0.048%.

Nb is a strong carbon and nitrogen compound forming element, recrystallization of steel is inhibited in rolling to refine grains, the steel mainly plays a role in fine-grain strengthening, and part of niobium carbon and nitride is precipitated in the cooling process after rolling, so that the steel is partially precipitated and strengthened. In addition, Nb is an expensive alloying element, and the Nb content is preferably controlled to 0.025% to 0.055% in the present invention in view of cost control.

V: vanadium is a medium carbon and nitrogen compound forming element, mainly plays a role in strong precipitation strengthening and weak fine crystal strengthening in steel, and the content of V is preferably controlled to be 0.050 to 0.12 percent by combining with alloy cost control.

Ti: titanium is an element formed by strong carbon and nitrogen compounds, and is precipitated in the cooling process after rolling to play a strengthening role. Meanwhile, a proper amount of Ti is added into the steel to form fine titanium carbonitride, so that the growth of crystal grains during heating can be effectively inhibited, and the effect of refining the crystal grains is achieved. However, too high Ti combines with N to form coarse TiN inclusions, which reduce the low temperature toughness and fatigue properties of the steel. Therefore, it is preferable that the Ti content is controlled to be between 0.070% and 0.15%.

B: the proper amount of boron added into the steel can inhibit the precipitation of proeutectoid ferrite and prolong the incubation period of austenite, so that a higher proportion of hardened tissues can be obtained in the subsequent phase transformation process, and the hardenability of the steel is obviously improved. Excessive B causes massive precipitation of B compounds in the steel at austenite grain boundaries, and seriously reduces the toughness of the steel. Therefore, the content of B in the present invention is preferably controlled to 0.0005% to 0.0050%.

N: nitrogen is a harmful element in steel, and excessively high nitrogen can combine with Ti to generate large-sized TiN inclusions, deteriorating cold formability and low-temperature impact toughness of the steel. Therefore, it is preferable that the N content is controlled to be within 0.0055%.

The invention has the beneficial effects that:

1) the high-strength and high-toughness steel for engineering machinery is produced by a one-step production method, does not need post-rolling heat treatment, and is high in production efficiency, low in process energy consumption, short in delivery period and convenient for large-scale tissue production.

2) And quantifying the correction value of the micro-Zhongunres rolling flatness of the secondary model to be-1 IU to-5 IU, optimizing the sequence of laminar cooling water outlet by adopting a front section interval cooling mode in laminar cooling, and simultaneously warehousing and slow cooling the steel coils on the lower line to improve the cooling uniformity of the strip steel and relieve the internal residual stress so that the final finished product obtains good plate shape.

3) The steel for engineering machinery produced according to the invention has the yield strength of over 800MPa, the elongation after fracture of not less than 18 percent, the low-temperature impact property at minus 40 ℃ of not less than 80J, and good toughness and toughness matching. The unevenness of the strip steel after flattening is controlled within 5mm/m, and the lateral bending amount of the strip steel after longitudinal cutting and splitting is controlled within 8 mm/through length.

The specific implementation mode is as follows:

the invention relates to a high-strength and high-toughness steel belt for engineering machinery, which comprises the following chemical components in percentage by weight: 0.03-0.12% of C, 0.04-0.24% of Si, 1.40-2.00% of Mn, less than or equal to 0.018% of P, less than or equal to 0.005% of S, 0.005-0.048% of Als, Nb: 0.025% -0.055%, V: 0.05 to 0.12 percent of Ti, 0.070 to 0.15 percent of Ti, 0.0005 to 0.0050 percent of B, less than or equal to 0.0055 percent of N, and the balance of Fe and inevitable residual elements.

Examples 1-8 were produced in accordance with the above-described embodiment, and the chemical composition in weight percent of the steel strip is shown in table 1.

TABLE 1 chemical composition control (unit: wt%)

The invention relates to a method for controlling the shape of a steel plate for high-strength and high-toughness engineering machinery, which comprises the working procedures of plate blank heating, rough rolling, finish rolling, controlled cooling and slow cooling after rolling. The production line of the Handover 2250 hot continuous rolling is explained below:

and a slab heating procedure, wherein the heating furnace keeps reducing or neutral atmosphere, the air-fuel ratio is 0.9-1.2, the slab discharging temperature is 1240-1300 ℃, the residence time of the slab in the soaking section of the heating furnace is 30-50min, and the total heating time is 160-350min, and the specific parameters are shown in Table 2.

TABLE 2 heating Process parameters of the slabs

And the rolling procedure comprises a rough rolling procedure and a finish rolling procedure, wherein the rough rolling procedure adopts 3+3 or 3+ 5 passes of rolling, namely the rough rolling R1 rack performs 3 passes of reciprocating rolling, the rough rolling R2 rack performs 3 passes of reciprocating rolling or 5 passes of reciprocating rolling, the reduction rate of the last two passes is controlled to be between 20% and 30%, and the accumulated reduction rate of the rough rolling is controlled to be between 65% and 90%. And in the finish rolling process, the inlet temperature of finish rolling is 900-.

TABLE 3 Main parameters of the Rolling Process

Note: the reduction ratios of the last 2 passes of rough rolling are listed in Table 3, for example, "22/28" where "/" is preceded by the reduction ratio of the last pass of rough rolling and "/" is followed by the reduction ratio of the last pass of rough rolling.

Controlling a cooling process, adopting a laminar flow cooling process, wherein the water temperature is 20-32 ℃, a front section interval cooling strategy is selected, a secondary model sets a coiling temperature target value to be 580 ℃, taking an embodiment 5 as an example, the detection temperature of a finish rolling outlet is 910 ℃, the value is fed back to the secondary model, the group 1, 3, 5 and 7 of front section collecting pipe cooling water is started in advance before the head of the strip steel enters into the layer cooling, the coiling temperature is higher after the strip steel is cooled, the group 9 of the front section and the group 11-13 of the rear section cooling water are increased by the secondary model, the group 9 of the cooling water comprises 4U-shaped pipes, the starting sequence is from back to front, the group 11-13 is a rear section cooling collecting pipe, and the starting sequence is from front to back; example 5 the average cooling rate during laminar cooling was 54 ℃/s and the average coiling temperature was 650 ℃, see table 4.

TABLE 4 Cooling Process Main parameters

The steel for engineering machinery produced according to the invention has the following mechanical properties: the yield strength is 827-851MPa, the tensile strength is 925-962MPa, the elongation is 19.5-24.2%, the full-scale impact energy at-40 ℃ is 86-168J, and the details are shown in Table 5.

TABLE 5 mechanical Properties of steels for engineering machines

Note: 1. in Table 3, the tensile test piece and the bending test piece were transverse test pieces.

D is the bending indenter diameter, and a is the bending specimen thickness.

And taking a longitudinal sample in the impact test, and preparing the sample according to the standard full size.

The actual unevenness of the steel for the engineering machinery produced according to the invention is 1.8-5.0mm/m after flattening, and the actual lateral bending amount of the steel for the engineering machinery after slitting and splitting is 3.5-8.0 mm/full length of the steel strip for strip material application, which all meet the strict requirements of the steel field for the shape of the plate in the engineering machinery.

TABLE 6 shape of slit, flat, slit and strip

。