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Vertical double-barreled shotgun receiver vacuum heat treatment

In the manufacturing stage of the vertical double-barreled shotgun, the quenching and oxidation deformation of the key component “casing” will be encountered. The riser casing is a high-precision gun with asymmetrical shape processed by CNC forming and milling, and it cannot be remedied once it is oxidized and deformed by heat treatment.

For the high-precision casing formed by CNC milling, it is required that the one-time assembly is successful without grinding and correction after heat treatment, and it is a difficult problem faced by the heat treatment industry to control the oxidation deformation of heat treatment. The medium carbon low alloy steel with good shape and suitable strength and toughness is easy to produce heat treatment deformation; its asymmetric shape structure is an important factor causing heat treatment deformation. In order to ensure product quality and solve the problem of oxidative deformation in heat treatment of riser casing, a double-chamber vacuum quenching furnace is used for non-oxidative heating and quenching; E-type clamping and supporting aids for casing are made, and the size of each groove shape of riser casing is controlled inside and outside of heat treatment. deformed.

Problems of riser casing in traditional heat treatment process

1) The CNC machining casing is deformed after heat treatment, which seriously exceeds the tolerance range of error.

2) The surface of the high-precision riser casing is oxidized after heat treatment.

Causes of oxidative deformation of riser casing during heat treatment

1) The material of the casing is medium carbon low alloy steel with good machine forming and suitable strength and toughness, but heat treatment deformation is also inevitable.

2) The asymmetric shape structure of the casing groove body causes heat treatment deformation.

Cassette size and requirements:

The product name is vertical double-barreled shotgun receiver; the material is 42CrMo; the technical requirements for heat treatment: hardness 45~50HRC. The inner and outer dimensions of the tail end of the casing and the groove end have small deformation, and the groove wall has no outward or inward warping deformation; the heat treatment surface of the high-precision forming casing is smooth and free of oxidation.

The schematic diagram of heat treatment of riser casing is shown in the figure. In order to solve the oxidation deformation of the riser casing, vacuum heat treatment is adopted. In the double-chamber vacuum quenching furnace, non-oxidative heating and quenching is carried out to provide a guarantee for the bright quenching of the casing and ensure that the surface of the casing is free from oxidation. The double-chamber vacuum quenching furnace requires a vacuum heating chamber and a vacuum quenching chamber, and the vacuum degree should reach below 10Pa. The temperature control ensures that the workpiece is heated at high temperature and the quenching process is continuously carried out under a fully enclosed high vacuum, so as to ensure the heat treatment quality of the casing.

Receiver tooling design:

The material of the riser casing is medium carbon low-alloy steel, which is prone to quenching deformation. Its U-shaped asymmetrical shape structure, the difference in thickness between the two facades and the tail end of the machine will cause uneven cooling and warping deformation.

For this, it is necessary to specially design and process an E-type clamping support aid, which is clamped between the two groove walls of the casing that are easy to warp, and the clamping block supports the two facades. The inward warping top wire is pressed against the outer surfaces of the two groove walls through the gasket to limit its outward warping. The gasket makes the jacking force evenly act on the casing groove wall, which can prevent the casing from being damaged during heating. The U-shaped groove of the casing is clamped by this auxiliary tool

After supporting, they are heated and quenched in a vacuum furnace together, which can make up for the original asymmetrical shape and structure, thus effectively preventing the deformation of the casing during high-temperature heating and quenching.

The assembly diagram of the heat treatment aids for the casing is shown in the figure:

The vacuum heat treatment process curve of the riser casing is shown in the figure:

Selection of vacuum heat treatment equipment: VOGQ series vacuum heat treatment furnace produced by SIMUWU is a high-quality product for vacuum heat treatment of parts. Good temperature control accuracy and temperature control uniformity ensure the effective progress of the vacuum heat treatment process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.