Hardening and tempering technology of alloy-steel tube

Abstract

The invention discloses a hardening and tempering technology of an alloy-steel tube, and through the technology, the hardened and tempered alloy-steel tube is high in intensity and hardness, has good abrasion resistance and high plasticity, bears great pressure, and has small deformation and less decarburization. The technology comprises the following steps of: (1) annealing treatment: warming to 870-880 DEG C at the speed of 20-25 DEG C/minute, keeping the temperature for 35-40 minutes, and then cooling to 500 DEG C below; (2) quenching treatment: warming to 930-935 DEG C at the speed of 5-10 DEG C/minute, keeping the temperature for 50-60 minutes, then cooling rapidly at the speed of 190-200 DEG C/second to 320-325 DEG C, and cooling naturally to 30-40 DEG C; and (3) tempering treatment: warming to 500-510 DEG C at the speed of 5-10 DEG C/minute, then keeping the temperature for 230-240 minutes, and then cooling naturally to room temperature, thus the hardened and tempered alloy-steel tube is high in intensity and hardness, has good abrasion resistance and high plasticity, bears great pressure, and has small deformation and less decarburization. The hardening and tempering technology of the alloy-steel tube provided by the invention is mainly applied to the hardening and tempering of the alloy-steel tube for a hydraulic cylinder barrel.

Description

technical field [0001] The invention relates to a quenching and tempering process for alloy steel pipes, in particular to a quenching and tempering process for alloy steel pipes used for preparing hydraulic cylinder barrels after cold drawing. Background technique [0002] The hydraulic cylinder is an important part of the hydraulic cylinder, and it is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion (or swing motion). When it is used to achieve reciprocating motion, the deceleration device can be eliminated, and there is no transmission gap, and the motion is stable, so it is widely used in various mechanical hydraulic systems. The hydraulic cylinder includes a cylinder, a cylinder head, a piston, a piston rod, a sealing device and a buffer device. The output force of the hydraulic cylinder is proportional to the effective area of ​​the piston and the pressure difference on both sides. Therefore, the compre...

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Problems solved by technology

[0019] 5. Surface roughness

[0033] 2. In the cold working state of the steel pipe, the tensile strength is 8.7% lower than the technical requirement, the yield strength is 11.2% lower than the technical requirement, the elongation is 21% lower than the technical requirement, the reduction of area is 33.8% lower than the technical requirement, and the hardness (HBW) is low 36.5% higher than the technical requirements, 60.3% lower than the technical requirements;

[0094] (2) Incomplete martensite transformation:

If the cooling rate is too fast (water tank cooling method), it will lead to uneven local cooling shrinkage, insufficient diffusion of substances in the tissue, and large internal stress, making the steel pipe prone to cracking and deformation

In addition, the traditional cooling medium (cooling water or cooling oil) cannot achieve the effect of rapid thermal diffusion cooling of steel pipes during quenching

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