On final heat treatment after forging organization and performance

Austenitic and ferritic heat-resistant stainless steel, high temperature alloy, aluminum alloy, magnesium alloy in the process of heating and cooling, no element with heterogeneous materials, and some of the copper alloy and titanium alloy, etc. , in the forging process of tissue defects by heat treatment does not improve. Element in the process of heating and cooling with heterogeneous transformation of materials, such as structural steel and martensitic stainless steel, etc. , due to improper forging process of some tissue defect or some defects of the legacy, raw materials has a great influence on the quality of heat treatment after forging. Is illustrated as follows: 1) Some organization defects of forging, heat treatment after forging can be improved, when forging eventually still satisfied with the organization and performance can be obtained after heat treatment. In general, for example, overheating of the structural steel forgings of coarse grain and widmanstatten structure, hypereutectoid steel and bearing steel caused by improper cooling slightly carbide network, etc. 2) Some forging tissue defects, using the normal heat treatment more difficult to eliminate, need high temperature normalizing, normalizing and low temperature decomposition over and over again, high temperature diffusion annealing and other measures to improve. Low power, for example, coarse grain, 9 cr18 stainless steel twin carbide, etc. 3) Some of the forgings organization defects, with general heat treatment process can't eliminate, final heat treatment after forging performance degradation as a result, even not qualified. Serious stone, for instance, fracture and the surface of the rib fracture, burnt, the ferritic stainless steel belt, carbide in ledeburite high alloy tool steel wire mesh, belt and so on. 4) Some of the forgings organization defects, in the final heat treatment will be further developed, and even cause cracking. Alloy structural steel forgings in the coarse grain structure, for example, if not improved, when the heat treatment after forging in carbon, nitrogen, and often cause martensite after quenching body acupuncture is bulky and performance is unqualified; Bulky banded carbide of high speed steel, quenching often cause craze. Common defects and their causes in the process of forging in forging a common defects in concrete is introduced. It should be pointed out that all kinds of forming methods of common defects and all kinds of materials is the main defect of forgings has its rule. Different forming methods, due to the different stress distribution, stress and strain characteristics are different, so it can be produced by the main defect is not the same. When, for example, billet upsetting is the main defect of the lateral surface longitudinal crack, or 45 ° direction after upsetting of ingot material, lower residual as-cast organization, etc. ; Rectangular section is the main defect of billet drawing long transverse cracks and Angle cracks on the surface of the interior of diagonal cracks and transverse cracks; When the open die forging is the main defect of discontent, folding and filling wrong move, and so on. The main common defects in forming process will be the main forming process of the common defects and countermeasures in detail. Different kinds of materials, due to the different composition, microstructure, in the process of heating, forging and cooling, its organizational change and mechanical behavior is also different, and so are not at that time, the forging process of defects also has its particularity. Ledeburite, for example, the defect of high alloy tool steel forgings are mainly carbide particles rough, uneven distribution and crack, the defect of high temperature alloy forgings are mainly coarse grain and crack; Austenitic stainless steel forgings defect is mainly intergranular chromium depleted, intergranular corrosion resistance drop, ferrite banded structure and crack, etc. ; The defects of aluminium alloy forgings are mainly coarse crystal, folding, eddy current, streams, etc