| High carbon content in Cast Iron made weldability of Cast Iron becomes low. However, upon application, Cast Iron sometimes require welding process, be it for connecting or repair. One application of Cast Iron is the wastewater, which generally use Nodular Cast Iron as base materials. Due to the low weldability, Nodular Cast Iron welding requires an additional process to get around, this process called preheating. Meanwhile, preheating depends on high and low temperature. High and low temperature of preheating were affecting the quality, microstructure and hardness the weld region. This is because the appearance of incomplete penetration at the preheating temperature lower than 250 ° C. Microstructure formed after welding was influential at the preheating temperature, which will also affect the hardness of the weld region. |