General purpose is to improve the mechanical properties, heat treatment of steel for the stainless steel, in addition to the guarantee of the mechanical properties of the purpose of heat treatment, also is to ensure that the steel has certain corrosion resistance, this is the particularity of the stainless steel heat treatment. In stainless steel valves, the commonly used stainless steel is 13Cr stainless steel, lCr17NI2 stainless steel and l 8-8 chromium nickel austenitic acid non-embroidered steel. The selection of these stainless steel, on the one hand, determines the selection of the valve, and on the other hand, the heat treatment performance and cold and heat processing properties of these steel.
The valve stem, valve pin, valve flap, valve cover, gate plate, packing pad and fastener used in stainless steel valve are often used in 13Cr stainless steel. The blanks of these valves should be hardened and tempered if they are made of bar materials. If they are forged, they should be softened after forging and tempering. 13 cr stainless steel respectively by the stainless steel valve principle is what heat treatment, heat treatment technology can meet the need of comprehensive performance, 13 cr not induced steel should slow cooling after forging, also should undertake softening. The softening treatment of the day is not only to reduce the hardness, to facilitate the machining and preparation of the subsequent heat treatment, but also to prevent the forging of the forging.
We know that after strong cooling, most of the cooling is air-cooled. The cooling rate is relatively fast. Due to the double influence of deformation and tissue transformation, the surface of 13Cr stainless steel forging is often cracked, which increases with the increase of carbon content in steel. Cracking occurs frequently in the actual production process if it is not cooled properly or softened in time. Therefore, 13Cr stainless steel not only needs to soften treatment, but also should be timely. According to the practical experience of a factory, it is very effective to keep the forging in the sand to cool slowly.