... 2. Welcome OEM 3. Make new moulds for you Square billet 150*150 27SiMn deformed steel bar ... , Black &AnnealingHardnessHBS=137~269Characteristic Applicationwelding is well, Used for making normal machinery parts, such as bolt, chain, ... hour;Furnace cooling to 770°C and hold at temperature for at least 10 hours;Cool by 10°C / ... heat treatment.Heat to 650-700°C, hold for 4/6 hours:Furnace cooling to 330-350 ...