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Comparison of Q245R, ASTM A516 grade 70, Q345R

2022-07-28

ASTM A516 Grade 70 Pressure Vessel And Boiler Steel Plate is used in Pressure Vessel,Boiler,Storage Tanks and Heat Exchange.

 

The strength of ASTM A516 grade 70 is slightly higher than Q245R, Close to but a bit lower than Q345R.

 

Most smelter in China, choose Q245R as the manufacturing material. Firstly, Q245R has less welding defects than Q345R, which is determined by its chemical composition. In addition, Q245R is better than Q345R in hydrogen corrosion resistance.

 

The main chemical elements affecting the corrosion of hydrogen sulfide are Mn and s. In the process of steel production and equipment welding, manganese produces high strength and low toughness microstructure of martensite / bainite, which shows extremely high hardness, which is extremely unfavorable for the equipment to resist hydrogen sulfide corrosion. In addition, non-metallic inclusions of manganese sulfide and iron sulfide are formed in the steel, resulting in local microstructure loosening and stress corrosion in wet hydrogen sulfide environment.

 

Table1 Chemical Composition

 

 

Chemical Composition(%)

 

C

Si

Mn

S

P

A516 Grade 70

0.27-0.31

0.13-0.45

0.79-1.30

≤0.035

≤0.035

Q245R

≤0.2

≤0.35

0.5-1.0

≤0.01

≤0.025

Q345R

≤0.2

0.2-0.55

1.2-1.6

≤0.01

≤0.025

Q245R (HIC)

≤0.2

≤0.35

0.5-1.0

≤0.004

≤0.015

Q345R (HIC)

≤0.2

0.2-0.55

1.2-1.6

≤0.004

≤0.015

 

Table2 Mechanical Property

 

 

Mechanical Property

 

Tensile Strength(MPa)

Yield Strength

(MPa)

% Elongation in 50mm  (min)

thickness

A516 Grade 70

485-620

260

17

36-60mm

Q245R

400-520

225

25

Q345R

490-620

315

21

 

Note: HIC resistant steel plate (hydrogen sulfide corrosion resistant steel plate):

 

1. Low P and S content, good resistance to wet hydrogen sulfide corrosion;

 

2. Hydrogen-induced cracking (HIC) performance test, the test method is in accordance with NACE TM0284 standard or GB/T 8650;

 

3. Excellent resistance to sulfide stress corrosion (SSCC) performance.

 

Comparison of Q245R, ASTM A516 grade 70, Q345R