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Defects In Industrial Prototype Heat Treatment And Its Prevention
Nov 03, 2017

Defects in Industrial Prototype heat treatment and its prevention
1. Industrial Prototype surface has a soft spot
Industrial Prototype heat treatment surface has a soft spot, will affect the wear resistance of Industrial Prototype, reducing the life of Industrial Prototypes.
(1) causes
1) Industrial Prototype surface before the heat treatment of oxide scale, rust and local decarburization. 2) quenching Industrial Prototype heating, quenching medium improper selection, excessive quenching medium impurities or aging.
(2) Preventive measures
1) Before the Industrial Prototype heat treatment, the scale and rust spots should be removed, and the surface of Industrial Prototype should be properly protected during quenching and heating. The vacuum furnace, salt bath furnace and protective atmosphere furnace should be used as far as possible to heat the Industrial Prototype surface. 2) Industrial Prototype quenching heating cooling, you should choose the right cooling medium, long-term use of cooling medium to be filtered regularly, or regularly replaced.
2. Industrial Prototype heat treatment before the poor organization
Industrial Prototype final spheroidal organizations coarse uneven, incomplete ball, the organization of mesh, ribbon and chain carbide, which will make the Industrial Prototype easily cracked after quenching, resulting in Industrial Prototype scrapped.
(1) causes
1) There is serious segregation of carbides in the original structure of Industrial Prototype steel material. 2) forging process is not good, such as forging heating temperature is too high, deformation is small, forging temperature is high, slow cooling after forging, etc., forging the organization coarse and mesh, ribbon and chain carbide existence, the ball When annealing is difficult to eliminate. 3) ball annealing process is poor, such as the annealing temperature is too high or too low, isothermal annealing time is short, etc., can lead to uneven microstructure or spheroidization poor annealing.
(2) Preventive measures
1) In general, the Industrial Prototype should be based on the working conditions, production volume and material itself toughening performance, try to choose good quality Industrial Prototype steel. 2) Improve the forging process or use normalizing heat treatment to eliminate the inhomogeneity of the mesh and chain carbides and carbides in the raw materials. 3) High-carbon Industrial Prototype steels with severe segregation of carbide that can not be forged can be subjected to solution heat treatment.
3. Industrial Prototypes produce quenched cracks
Industrial Prototype cracking after quenching is the biggest defect in the process of Industrial Prototype heat treatment, will make the finished Industrial Prototype scrapped, resulting in great losses in production and economy.
(1) the causes
1) There is a serious mesh carbide segregation in Industrial Prototype materials. 2) There are mechanical processing or cold plastic deformation stress in the Industrial Prototype. 3) improper operation of Industrial Prototype heat treatment (heating or cooling too fast, quenching improper selection of cooling medium, cooling temperature is too low, cooling time is too long, etc.). 4) The Industrial Prototype complex shape, uneven thickness, with sharp corners and threaded holes, so that thermal stress and tissue stress is too large.
(2) Preventive measures
1) Strict control of the intrinsic quality of Industrial Prototype materials 2) Improve the forging and ball annealing process to eliminate the reticular, banded, chain-like carbides and improve the homogeneity of the spheroidized structure. 3) Industrial Prototypes after machining or after cold plastic deformation should be stress-relief annealed (> 600 ° C) before being heat-hardened. 4) The shape of complex Industrial Prototype should be asbestos plugging threaded holes, banding dangerous sections and thin-walled Department, and the use of graded or isothermal quenching. 5) When reworking or refurbishing Industrial Prototypes, annealing or tempering is required.