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. The swaged nipple is also called the reducing nipple, usually using the American standard MSS SP-95, the common material is carbon steel, stainless steel, alloy steel. Reducing pipe (reducing nipple) is a pipe fitting for the straight connection of two pipes of different sizes to achieve pipe reducing. There are concentric reducing joints and eccentric reducing joints. The center line of two pipes connected by concentric reducing joints is in a straight line, which is mainly used for vertical pipelines. Eccentric reducing joints are mostly used in horizontal pipelines. Reducing joint with straight edge section,GB12459(DN20x15~500~300) made of seamless steel pipe; Without straight side section reducer,GB/TI.MOI(DN350×300~1200×1000) is made of steel plate or steel strip. Generally, reducing joints for large-diameter pipe connections are made of steel plate or steel strip, which is cheap and economical, but without straight edge section, and the alignment at the welding groove is more difficult than that of reducing joints with straight edge section. In small diameter pipelines (DN50 or less), reducing joints are often used instead of reducing joints for pipeline reducing. Reducing segments are also concentric and eccentric.