Stainless steel has forging properties similar to carbon steel and low alloy steel. It can be formed by different forging methods on different forging equipment. The only difference is that at forging temperatures, stainless steels have higher flow stress than carbon and low alloy steels; second, some stainless steels, such as austenitic-ferritic duplex stainless steels and martensitic stainless steels, are heated to forging At temperature, there is a second phase - α (δ) ferrite on the grain boundary. Because of its different mechanical properties and recrystallization conditions from the r-phase of the matrix, the plasticity of stainless steel is greatly reduced.
Due to the narrow forging temperature range of stainless steel and low initial forging temperature, for example, the maximum forging temperature of high-chromium martensitic stainless steel is 55-165 °C lower than that of general low-alloy steel, so a larger forging load is required, compared with 40CrNiMo steel. , with the increase of chromium content, the forging load of martensitic stainless steel increases by 20% to 100%; the force required for forging precipitation hardening stainless steel is 30% to 50% higher than forging 40CrNiMo steel. The average unit flow stress of austenitic stainless steel 0Cr18Ni9 at different upsetting amounts is compared with the average unit flow stress of 20 steel. Figure 3 shows the average unit flow stress of these two steels at different temperatures. It can be seen from the figure that at 982°C (1800F) and any degree of deformation greater than 6%, the average unit flow stress of forged 0Cr18Ni9 stainless steel is at least twice that of 20 steel.
