Alloy C-4 is an austenitic nickel-molybdenum-chromium alloy with a low carbon, silicon, and iron content. This alloy has a significantly lower tendency to form precipitation in the temperature range between 650 and 1,040 °C(1,202 - 1,904 °F), improving its resistance to inter-crystalline corrosion. When machined perfectly, no knife line attack occurs in the heat-affected zones of awelding edge. Alloy C-4 is characterized by: Very good resistance in a broad field of corrosive media, in particular under strongly oxidizing conditions. Excellent resistance to pitting, crevice and stress corrosion. Threaded tee is a kind of industrial pipe fittings, its main function is to divide the medium through. Thread tee in the production process is divided into forging and casting two kinds, forging refers to the ingot or round rod heated forging forming, after the lathe processing thread, casting refers to the ingot melted into the model of the tee, to be cooled after. Because of the different manufacturing process, the size of the pressure is different, and the pressure resistance of forging is much higher than that of casting.