Preparing process of alloy-steel pipe used for hydraulic cylinder tube

Abstract

The invention discloses a preparing process of an alloy-steel pipe used for a hydraulic cylinder tube, which can avoid a surface decarburization phenomenon and deformation. The preparing process comprises the following steps of: a, surface treatment: the external surface polishing and inner hole honing are carried out on a hot rolling round alloy-steel pipe; b, annealing heat treatment: the hot rolling round alloy-steel pipe after the surface treatment is heated to 880-900 DEG C, and the heat preservation is carried out for 50-60 minutes; c, drawing molding: the hot rolling round alloy-steel pipe after annealing treatment is subjected to natural cooling, the surface of the hot rolling round alloy-steel pipe is lubricated and then drawn into the required size; and d, aging heat treatment: the hot rolling round alloy-steel pipe after drawing molding is heated to 300-320 DEG C, the heat preservation is carried out for 250-300 minutes, and the alloy-steel pipe used for the hydraulic cylinder tube is obtained after cooling. The preparing process provided by the invention has the advantages that the aging heat treatment process is adopted, and the hydraulic cylinder tube which has the advantages of high intensity, high hardness, good wearability, strong plasticity, large bearing pressure, no transformation and no decarburization phenomenon is obtained.

Description

technical field [0001] The invention relates to a preparation process of an alloy steel pipe in the technical field of metal rolling processing and metal material heat treatment, in particular to a preparation process of an alloy steel pipe for a hydraulic cylinder. Background technique [0002] Alloy steel is widely used in various mechanical parts and structural parts. In actual production, since alloy steel contains alloy elements, when the product structure has mechanical and process performance requirements, alloy steel usually adopts quenching and tempering (quenching + tempering). Fire) heat treatment process, the defect of this process is: [0003] 1. The production cycle is long and the process is complicated; [0004] 2. The cost of quenching and tempering is too high, which limits the scope of application of the product; [0005] 3. After quenching and tempering heat treatment, the product is deformed and the dimensional accuracy is greatly reduced; [0006] 4....

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Problems solved by technology

[0003] 1. The production cycle is long and the process is complicated;

[0004] 2. The cost of quenching and tempering is too high, which limits the scope of application of the product;

[0005] 3. After quenching and tempering heat treatment, the product is deformed and the dimensional accuracy is greatly reduced;

[0006] 4. The surface finish of the product decreases, accompanied by decarburization

[0024] 5. Surface roughness

[0036] 1. After the alloy steel pipe is tempered (or normalized), due to the influence of high temperature heating, the surface of the alloy steel pipe produces oxide scales (Fe2O3 and Fe3O4), and the roughness drops sharply. The surface roughness is reduced from 3.2 μm to 12.5 μm, which cannot meet the requirements Technical requirements for making cylinder barrels;

[0037] 2. After high-temperature quenching, affected by the rapid cooling of the cooling medium, the phenomenon of thermal expansion and contraction occurs instantly, and the residual stress of the cold-drawn alloy steel pipe itself is poor. The original geometrically accurate alloy steel pipe undergoes large deformation after quenching and tempering. The expansion of the outer diameter is close to 0.9mm, the expansion of the inner diameter is close to 0.8mm, and the expansion of the ellipticity is close to 0.7mm. The geometric dimension accuracy is far below the technical requirements of the cylinder barrel, and cannot meet the technical requirements of the production of the cylinder barrel;

[0038] 3. Although the decarburization phenomenon on the surface of the alloy steel pipe can be reduced or reduced during quenching and tempering (or normalizing) heat treatment, and the depth of the decarburization layer can be reduced. However, since the above-mentioned processes are all high-temperature heat treatment processes, the decarburization phenomenon cannot be avoided.

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