Material Technology

At BW, we choose materials very cautiously. Even though the materials are certificated, our lab still runs multiple tests to ensure chemical and mechanical properties. Also, we provide specific material solution upon customer’s requirement.

Sulfur and Phosphorus are the impurities that are brought into steel by pig iron. When Sulfur and Iron are mixed, they undergo a chemical reaction and form a new substance ferrous sulfide (FeS).  The amount of Sulfur that in Iron would affect the hot brittleness. FeS and Fe forms a eutectic distributes on austenite grain boundaries with low melting point (985°C). When iron is heated to 1,200°C, the eutectic melts and causes intergranular fracture.

Phosphorus would increase the strength and hardness in iron but decrease the plasticity and toughness significantly. Phosphorus increases the tendency of a metal to become cold-short, that is,  

brittle at reduced temperatures. In the process of crystallization, the amount of Phosphorus tends to increase in a certain area which would cause temperature rising and brittle failure.

Non-metallic inclusions have great impacts on the strength, plasticity, fracture toughness, cutting, fatigue, heat brittleness and corrosion resistance. Based on the amounts of harmful impurities (S and P) and non-metallic inclusions, distinctions are made between General Purpose, Quality, Premium, and Air-Space grade steels.

BW only uses the high purity steel with low concentration of elements such as Phosphorus, Sulfur, etc. The standard percentage of Sulfur and Phosphorus is ≤0.02%, BWs is controlled to 0.003% and 0.007%. BW values our raw material selections as important as our machining process.