Heating and stretching

　　The heating and final pressing temperature of the head blank, details can be seen below

　　Special steel grades are executed according to special processes, and stainless composite steel plates are heated according to composite layer requirements

　　Material Q235A, 20R Heating 1000℃-1050℃ Final pressure ≥700℃

　　Material 16MnR、15MnVR、15MnVNR、12CrMoR、15CrMoR、12Cr2M01R 950-1050 Heating 950℃-1050℃ Final pressing ≥700℃

　　Material OCr18Ni9、1Cr18Ni9Ti、1Cr18Ni9、00Cr19Ni11、0Cr18Ni11Ti、1Cr19Ni9、00Cr17Ni14Mo2、00Cr17Ni12Mo2Heating 950℃-1100℃ Final pressing ≥850℃

　　When the blank in the heating furnace, it needs to be supported by a bracket. When multiple blanks are heated immediately, 50~100mm thick pads should be added between the blanks. The blanks must not overlap to prevent over-burning or impermeability. The concave surface of the embossed head blank should face upwards. The composite layer of the composite board blank is upward.

　　When the process requires a head with a heat treatment verification test plate, the test plate shall be installed in the furnace at the same time as the blank of the head and discharged at the same time.

　　When the blank is heated to 800 ~ 850℃, it should be thermally insulated at a thickness of 0.8min/mm. After the temperature of the blank is uniform, continue to heat up to the heating temperature to prevent overheating or overburning.

　　After the head blank is released from the furnace, it must be immediately lifted onto the tire mold to ensure the head stamping temperature.

　　The speed during stretching should be uniform and suitable.

　　The final pressure temperature of the hot-pressed carbon steel head should not be lower than 700℃, and generally no heat treatment is performed. However, if the final pressure temperature is less than 700℃, stress relief annealing must be performed. Sealing heads with special requirements shall be implemented according to special processes.

　　The heads of stainless steel and stainless composite steel shall be heated (or cooled) rapidly within the range of 450℃～850℃ and the final pressure temperature shall not be lower than 850℃, otherwise they shall undergo solution treatment.

　　After the head is demoulded, it needs to be cooled to below 550℃ before it can be hoisted to prevent deformation.