0Cr17Mn13Mo2N (A4) Urea Grade Duplex Stainless Steel- SCALE STEEL.

​0Cr17Mn13Mo2N is a type of Cr-Mn-N section nickel stainless steel developed by our country, usually referred to as A4 steel, steel with [SCALE STEEL]austenite, ferrite two-phase structure.

Component Specification（GB 1220-75）
C ≤0.08 Cr 16.5~18.5
Si ≤0.70 Mo 1.80~2.20
Mn 12.0~15.0 N 0.20~0.30
P ≤0.045 S ≤0.020

 Mechanical Property
heat treatment condition 1050~1100℃, and water
strength of extension MPa[SCALE STEEL] ≥736
yield MPa ≥441
percentage elongation after fracture % ≥30
hardness HB ≤255

Material characteristics
As a dual-phase stainless steel, A4 steel is less prone to intergranular corrosion and stress corrosion than austenitic stainless steel, and its mechanical properties and welding properties are better.Due to the existence of δ ferrite [SCALE STEEL]phase, σ phase is easily formed, and the cold and hot working properties of steel are poor.

Urea level:
The intermediate reaction product in urea production, urea-ammonium chloride solution, is strongly corrosive to stainless steel at high temperature and high pressure, which can destroy the passivation film of stainless steel and has a strong depassivation effect, so that Cr-Ni austenitic stainless steel containing [SCALE STEEL]Mo2% ~ 3% is difficult to resist corrosion, and A4 steel has good corrosion resistance.

Applications:
A4 steel corrosion resistance is superior to the 1 cr18ni12moti in acetic acid, can replace 1 cr18ni9ti in phosphoric acid, [SCALE STEEL]has good corrosion resistance to urea, urea equipment is mainly used for making the whole cycle method, such as synthetic tower, high pressure separator and so on, also can be used in synthetic fiber industry, such as saran made production, also used in other chemical, fertilizer and other industrial department of equipment and parts.