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Why must stainless steel thick-walled pipes be forged?

The semi-austenite deposition hardness is higher than that of stainless steel thick wall pipe and martensite precipitation hardening stainless steel through the combination of martensite transformation and precipitation heat treatment.These steel is the hardest to forge and will crack if it is not strictly in accordance with the temperature regime.They are forging temperature range is very narrow, if forging temperature below 982 ℃, the secondary heating.Generated in the grain growth and ferrite, the steel under any set of forging temperature, the plastic is very poor (good) rigidity, therefore, if you want to make with other types of stainless steel thick wall tube plastic deformation, the same forging will need to use the impact of the heavy forging hammer and more times.

During the dressing, the forging must be kept at a high enough temperature to prevent edge cracking.In order to avoid these cracks, the forging parts are usually heated slightly between final forging and finishing operations.In addition, the cooling of the forgings must be controlled, especially the martensitic stainless steel in case of cracking.

In the following example, a typical process of forging slender forgings is presented. The material is 17-4ph, with 396.6mm short rod blank, forging long and slender forgings of 1168.4mm.The forging of two steam hammers requires a six-step process.The first step is to stretch it into 65.5mm square billet.The second step is to forge it into 50.8mm square billet.The third step is to forge it into the width of the final forging die.The fourth step is to rotate it by 90.And cutting head;Step 5 preforging;Step 6 complete the forging.

Since this type of stainless steel thick-walled pipe is forged at a narrow temperature range, secondary heating is required before final forging.Heating time, heating temperature of 117 ℃, 1 h for the first time, second time 1.5 h.The heating atmosphere is a micro-oxidation atmosphere, and the lubricant USES graphite oil.Stainless steel thick wall pipe thick wall stainless steel pipe large diameter thick wall pipe large diameter thick wall pipe large diameter thick wall pipe stainless steel pipe.




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