Cronifer 2803

Based on HuaNickel Cr28Mo4 super ferritic stainless steel, the amount of C+N is controlled and ~4%Ni is added to improve the toughness of the steel, especially to reduce the brittle transition temperature of the steel. Niobium stabilization can not only prevent the decline of alloy toughness caused by the addition of titanium to form TiN, but also reduce the sensitivity of intergranular corrosion of steel by taking advantage of the stronger ability of niobium than titanium to fix carbon, and the adverse effect of niobium on the brittle transition temperature of steel is weaker than that of titanium and can refine grains.

Cronifer 2803Chemical composition：

	Cr	Ni	Mo	C	Si	Mn	S	P	N	C+N
Min	28	3	1.8	≤
Max	29	4	2.5	0.015	0.5	0.5	0.03	0.03	0.02	0.03

Cronifer 2803Physical properties：

Density /g·cm-3	Specific heat capacityc /J·(kg·K)-	Thermal conductivity λ /W·(m·K)-	Coefficient of thermal expansiona/10-6·K-(20～300℃)	Elastic modulusE /kN·mm-2
7.7	400	14.5	10.5	215

Cronifer 2803Mechanical properties：

Heat treatment status	σp0.2/MPa	σb/MPa	δ/%	Hardness(HRB)	Impact power/]
Annealed state	≥450	≥565	≥18	≤100	110Longitudinal

Cronifer 2803Alloy properties：

As with all high-chromium-molybdenum ferritic stainless steels, this steel is annealed in a body-centered cubic pure ferrite structure. At ~475°C, there will be α’ phase precipitation, and at medium temperature (e.g. ~800°C), there will be σ phase precipitation, resulting in a decrease in toughness and corrosion resistance.

Cronifer 2803Uses of alloys：

It is mainly used for equipment in the cooling system of seawater and Cl~ water for conventional and nuclear power plants, and can also be used for related devices of seawater desalination plants; Due to the good performance of this steel to resist F-, Cl-phosphoric acid and high temperature and high concentration of sulfuric acid, it can also be used as equipment and pipelines for production, storage and transportation in phosphate fertilizer plants and sulfuric acid production plants.

Cronifer 2803Process performance：

Welding process: They are mainly welded with inert gas arc welding (e.g., TIG welding with or without wire filling). At the same time, the weldment should be carefully cleaned before welding, and the pollution and oxidation color should be cleaned up in time after welding.

Heat treatment: This steel can be treated at 950~1050 °C, and it is quickly cooled after heating and insulation.

Relevant standards：

ASTM A176、ASTM A240、ASTM A268