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What is the impact of high phosphorus and sulfur content on the performance of stainless steel tubes?

What is the impact of high phosphorus and sulfur content on the performance of stainless steel tubes?

Time:2022-03-18 Source:China Wuxi JiaNuo Special Steel Co.

Some harmful phosphorus and sulfur impurities mixed into the steelmaking furnace, causing difficulties in the production of steel, affecting the quality of stainless steel tubes, and even causing waste. Slag formed by non-metallic impurities will erode the furnace lining, reduce the age of the furnace, increase the consumption of auxiliary materials and energy. Wenzhou stainless steel pipe to extend the smelting time, reduce production and increase costs. It can also cause air pollution. In particular, explosives are mixed into the furnace and explode at high temperatures, causing personal and equipment accidents.

Phosphorus is a harmful element in stainless steel pipe. One of the sources of phosphorus is the high phosphorus steel scrap mixed in the scrap. For example, agricultural machinery castings and high phosphorus residual iron produced from high phosphorus iron ore. If the phosphorus content exceeds the limit, the strength and hardness of the stainless steel pipe will increase significantly, the toughness and plasticity of the pipe will be reduced, and the steel will become brittle at low temperatures. This phenomenon is known as “cold brittleness” and occurs when the steel is cold worked. Cracking. Phosphorus also increases the weld susceptibility of the steel, which is detrimental to the welding process of stainless steel tubes. The high phosphorus content of recycled steel and steel will increase the auxiliary materials and energy consumption of steelmaking, extending the smelting time and increasing the production costs of stainless steel pipe mill. It is very difficult to remove phosphorus in steelmaking production. Therefore, the phosphorus content in the scrap must be strictly controlled. When supplying the charge, the scrap steel containing too much phosphorus needs to be carefully selected and reduced. Sulfur is also a harmful element in stainless steel pipe. When the sulfur content in steel is greater than 0.06%, cracking occurs during hot rolling, forging or heat treatment. Wenzhou stainless steel tube manufacturer this cracking phenomenon is called “thermal embrittlement”. Sulfur is also formed in the steel pipe sulfide (such as manganese sulfide, etc.), which is embedded in the steel to reduce the ductility and toughness of the steel pipe. Sulfur in steel can also deteriorate the weldability of steel. It often leads to thermal cracking of welded joints. At the same time, sulfur tends to form sulfur dioxide gas during the welding process, which can create a large number of pores in the weld, leading to weld loosening and affecting the quality of the weld. The high sulfur content in the steelmaking process will increase the consumption of steelmaking auxiliary materials and electrical energy, extend the smelting time, and increase the cost of stainless steel pipe production. In the scrap, high sulfur content is: high sulfur iron, fire iron, furnace, grate, etc.. It is necessary to carefully clean and classify the supply.

Carbon is not considered a harmful element in stainless steel tubes. However, in steelmaking, depending on the use of steel use carbon, and different uses of steel has strictly different carbon content. The amount of carbon in stainless steel pipe has a great impact on the performance of the pipe. In general, the higher the carbon content of stainless steel pipe material, the higher the strength and hardness of the steel pipe, the lower the plasticity and toughness; the lower the carbon content of stainless steel pipe material, the lower the strength and hardness of the steel, the higher the plasticity, the higher the toughness. The carbon content of the scrap has a great impact on the steelmaking operation. If the carbon content is too high or too low, it will increase the consumption of auxiliary materials and prolong the smelting time. Therefore, scrap for steelmaking must be strictly separated according to the carbon content.

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