Manufacturing method of wear-resistant chain assembly for stone picking machine

Abstract

The invention belongs to the field of production and processing of agricultural implements, and particularly relates to a manufacturing method of a wear-resistant chain assembly for a stone picker. The assembly specifically refers to a chain pin shaft, high-hardenability boron steel is selected as a raw material, and the high-hardenability boron steel comprises the following chemical components in percentage by weight: 0.35-0.42% of C, 0.8-1.6% of Mn, 0.17-0.37% of Si and Cr < lt >; 0.45, Ti < lt >; 0.05, Al < lt >; 0.06, P < lt >; 0.035, S < lt >; 0.035% of B, 0.0008-0.0030% of B, and the balance Fe; a tempered martensite structure is obtained through quenching and tempering treatment; the surface of the pin shaft is treated through laser quenching; and finally, the assembly requirement is met through accurate grinding. Aiming at the requirement that the chain for the stone picker needs to have good wear resistance, material and production process improvement is carried out on weak components in the using process of the chain for the domestic stone picker, and the manufacturing method of the pin shaft with good wear resistance and toughness indexes is developed.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of production and processing of agricultural implements, and particularly relates to a manufacturing method of a wear-resistant chain assembly pin shaft for a stone picker. BACKGROUND

[0002] There are a large number of stone lands with different degrees of stoniness in the cultivated land in the black soil region of Northeast China, Xinjiang and the mountainous region of Southwest China, and the sizes of the stones are different from 3 cm to 60 cm. During the process of mechanized tillage, the stones are turned out and scattered in the field, which causes the aggravation of the wear of the implements during the subsequent operation, and even the normal operation cannot be carried out. When sowing, the stones scattered on the surface and covered under the surface layer can also cause the wear and damage of the sowing machinery. A large number of scattered and different stones can also affect the growth of crops, reduce the germination rate, and the stones can also make the crops not to be properly hilled, thereby affecting the growth of crops and the harvest of grain. Whether it is the conventional field mechanical operation or the current demand of high-standard farmland construction, the cleaning of the stones in the cultivated land has gradually become an important link in the process of tillage, and therefore, the market demand for the stone picker in farmland is increasing. At present, there are various types of stone pickers in the international market, and the implements have different functions, stable structure and good durability, but the price is high. The structure of the domestic stone pickers is single, the cost is low, but the operation efficiency is low and the quality stability is poor.

[0003] The conveying chain is one of the key components of the stone picker, and the cost, service life and quality stability of the chain are important parts of determining the quality of the stone picker. As a kind of small agricultural implement, the application scene of the stone picker is mainly limited to farmland reclamation and high-standard farmland transformation, and there is no chain product on the market that fully meets the use demand of the stone picker, and there is no related research on the demand of the chain for the stone picker. Therefore, the stone picker production enterprises can only choose the chain products circulating in the market, which makes the chain the largest component of the production cost of the stone picker. However, the service life of the chain used by the stone picker in China is only 4-6 months, and it is difficult to replace, which further increases the cost of using the stone picker. SUMMARY

[0004] In view of the problems in the prior art, the application provides a manufacturing method of a wear-resistant chain assembly for a stone picker. The stone picker chain is mainly composed of an inner chain plate, an outer chain plate, a pin shaft and a sleeve, etc. The sleeve with good quality on the market basically meets the use demand of the stone picker chain, and the preparation method of the application is mainly applied to the preparation of the pin shaft and the chain plate of the stone picker chain assembly.

[0005] The technical scheme of the application is: The application discloses a manufacturing method of a wear-resistant chain assembly for a stone picker, and in particular to a chain pin shaft; high hardenability boron steel is selected as a raw material, and the chemical components of the high hardenability boron steel include the following in percentage by weight: C 0.35-0.42, Mn 0.8-1.6, Si 0.17-0.37, Cr<0.45, Ti<0.05, Al<0.06, P<0.035, S<0.035, B 0.0008-0.0030, and the rest is Fe; a tempered martensite structure is obtained through quenching + tempering treatment; the surface of the assembly is treated by laser quenching; and finally, the assembly is processed by fine grinding to meet the assembly requirements. Further, the manufacturing method of the wear-resistant chain assembly for the stone picker, the pin shaft of the assembly is treated by quenching + tempering to obtain good strength, toughness and hardness; the quenching temperature is 850-920 DEG C, the holding time is 10-30 min, the tempering temperature is 200-350 DEG C, and the holding time is 60-90 min.

[0006] Further, the manufacturing method of the wear-resistant chain assembly for the stone picker, the laser quenching adopts a laser surface quenching system, the power is 1500-2000 W, the scanning speed is 200-350 mm / min, the spot length is 5-10 mm, the hardened layer depth is controlled in the range of 1.0-2.0 mm, the surface martensite structure is ensured to be complete, and the matrix performance is unchanged. Further, the manufacturing method of the wear-resistant chain assembly for the stone picker, the assembly blank is prepared by using a round steel, after blanking and semi-finishing, the assembly blank enters a heat treatment process; the semi-finishing reserved grinding allowance is 0.5-1.0 mm, so as to adapt to subsequent fine grinding. Further, the manufacturing method of the wear-resistant chain assembly for the stone picker, the hardness of the final assembly matrix is greater than or equal to 50HRC, the impact toughness is greater than or equal to 25J / cm²; the surface hardness is greater than or equal to 56HRC, the hardened layer thickness is greater than or equal to 1 mm; compared with a conventional chain, the wear-resistant service life is increased by more than 30%, and the production cost is reduced by 20%.

[0007] Advantages and beneficial effects of the application: 1. The surface hardness and hardened layer depth of the chain pin shaft produced by the application are slightly better than those of a conventional high-quality chain.

[0008] 2. The matrix hardness of the chain assembly produced by the application is much higher than that of a conventional chain, after external hardened layer wear, the matrix also has good wear resistance, and the service life of the chain can be effectively improved. DRAWINGS

[0009] Figure 1 Microstructure of the core part of the stone picker pin shaft produced by the application; Figure 2 Microstructure of the surface hardened layer of the stone picker pin shaft produced by the application; Figure 3The microstructure of the hard layer and the core of the pin shaft of the domestic stone picker chain. DETAILED DESCRIPTION

[0010] The specific embodiments of the present application will be further described in detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0011] In the following examples, manganese-boron steel hot-rolled plates with a carbon content of 0.35% to 0.42% (mass fraction) are used to produce stone picker chain assemblies.

[0012] Example 1

[0013] The present example provides a manufacturing method for a pin shaft of a wear-resistant chain assembly for a stone picker. The stone picker pin shaft assembly is produced by machining round steel, and the main chemical components (wt%) thereof are: C: 0.36, Mn: 1.29, Si: 0.25, Cr: 0.15, B: 0.002, and the balance is Fe. The specific manufacturing method includes the following steps: (1) The round steel is cut according to the required size for forming; (2) The pin shaft mounting hole and the shaft part semi-finishing are completed. The semi-finishing allowance for grinding is 0.5 mm to adapt to subsequent fine grinding; (3) Quenching + tempering treatment is performed using a tooling mold. The quenching temperature is 900°C, the holding time is 20 min, the tempering temperature is 200°C, and the holding time is 60 min. The microstructure after quenching is shown in Figure 1 ; (4) Surface quenching is performed using a laser surface quenching system. The power is 1500W, the scanning speed is 200mm / min, the spot length is 5mm, and the quenching layer depth is controlled at 1.6mm to ensure that the surface martensite structure is complete and the matrix performance is unchanged; (5) Fine grinding is performed on the pin shaft assembly area.

[0014] The core and the surface hard layer of the pin shaft manufactured in the present example are subjected to multi-point hardness detection. The core hardness is: 50.9, 50.5HRC, 50.7HRC, 50.4HRC, 50.1HRC, 50.2HRC; and the surface hard layer hardness is: 57.2HRC, 57.5HRC, 57.3HRC, 57.9HRC, 57.7HRC, 57.4HRC.

[0015] The impact toughness index of the pin shaft of the chain assembly in the present example after quenching + tempering treatment is detected to be within 26-28J / cm 2 , which meets the design requirements. The actual thickness of the surface hardened layer is 1.1-1.5mm, as shown in Figure 2 . Compared with the thickness of the carburized layer of the domestic chain pin shaft, the thickness of the hard layer is increased by 1-2 times, as shown inFigure 3 .

[0016] Example 2

[0017] The embodiment provides a manufacturing method of a pin shaft of a wear-resistant chain assembly of a stone picker, which is different from the embodiment 1 in that the pin shaft assembly of the stone picker is produced by hot die forging of round steel, and main chemical components (wt%) of the pin shaft assembly are as follows: C: 0.42, Mn: 0.88, Si: 0.27, Cr: 0.33, B: 0.0023, Al: 0.03, and the rest is Fe. The manufacturing method is different from the embodiment 1 in that: the hot die forged pin shaft blank is semi-finished, and a grinding allowance of 1.0 mm is reserved; in the quenching and tempering process, the quenching temperature is 860 DEG C, the holding time is 15 min, the tempering temperature is 250 DEG C, and the holding time is 90 min; in the laser quenching process, the power is 2000 W, the scanning speed is 350 mm / min, the spot length is 10 mm, and the hardened layer depth is controlled within 2.0 mm.

[0018] after the quenching and tempering process of the chain assembly pin shaft in the embodiment, the core hardness is 50-51 HRC, the surface hard layer hardness is 57-59 HRC, the impact toughness index can reach 25 J / cm 2 , the design requirement is met, and the actual measured thickness of the surface hardened layer is 1.0-1.4 mm.

Claims

1. A method for manufacturing a wear-resistant chain assembly for a stone-collecting machine, characterized in that, The component is specifically a chain pin; high hardenability boron steel is selected as the raw material, and its chemical composition by weight percentage includes: C 0.35~0.42, Mn 0.8~1.6, Si 0.17~0.37, Cr <0.45, Ti <0.05, Al <0.06, P <0.035, S <0.035, B 0.0008~0.0030, with the balance being Fe; tempered martensite structure is obtained through quenching and tempering treatment; the surface of the component is then treated with laser quenching; finally, it is precision ground to meet assembly requirements.

2. A method for manufacturing a wear-resistant chain assembly for a stone-picking machine according to claim 1, characterized in that, The component pin is subjected to quenching and tempering treatment to obtain good strength, toughness and hardness; quenching temperature is 850-920℃, holding time is 10-30min, tempering temperature is 200-350℃, holding time is 60-90min.

3. A method for manufacturing a wear-resistant chain assembly for a stone-picking machine according to claim 1, characterized in that, The laser quenching adopts a laser surface quenching system with a power of 1500-2000W, a scanning speed of 200-350mm / min, a spot length of 5-10mm, and a hardened layer depth controlled within the range of 1.0~2.0mm to ensure the integrity of the surface martensitic structure and the unchanged matrix properties.

4. A method for manufacturing a wear-resistant chain assembly for a stone-picking machine according to claim 1, characterized in that, The component blanks are made of round steel, which are cut, semi-finished and then heat treated. The semi-finished machining allows for a grinding allowance of 0.5-1.0 mm to accommodate subsequent fine grinding.

5. A method for manufacturing a wear-resistant chain assembly for a stone-picking machine according to claim 1, characterized in that: The final component has a matrix hardness of ≥50HRC, an impact toughness of ≥25J / cm², a surface hardness of ≥56HRC, and a hardened layer thickness of ≥1mm. Compared with conventional chains, the wear life is increased by more than 30%, and the production cost is reduced by 20%.

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