What Are Our Concerns About Bearings（57）

Q1:Is ASTM A105 alloy steel?

A:A105 is the American ASTM standard number, and A stands for ordinary carbon structural steel. 

Standard name: Carbon steel forgings for pipe parts.  Because this standard only provides a carbon steel forgings, A105 also counts as a forged carbon steel brand.

C:≤ 0.35Si :≤ 0.35Mn: 0.6-1.05s :≤ 0.050P :≤0.040  

The mechanical properties are between 20 forged steel and 16Mn forged steel.  ASTM A105 is carbon steel, not alloy steel

Q2:What kind of steel is A350LF6?

A:1: Carbon steel and low alloy steel forgings for pipe parts that require notch toughness tests in ASTM A350 are the American standard.  

2: LF6 is the material number in the standard, the chemical composition of the material C< 0.22%Mn0.6-1.35, due to the -40 low temperature impact requirements, it is equivalent to China’s Q345E, CL2 forgings grade: grade 2 forgings. 

Q3:What is the difference between TP304 and 304？

A:TP304 generally refers to the grade of stainless steel pipe in foreign standards, the most typical is the grade of stainless steel pipe in American ASTM and ASME standards.  For example: ASTM A312-09 TP304.  And 304 refers to the foreign stainless steel brand, it is not China’s national standard of stainless steel brand, Chinese people always like to mix up foreign brands, it seems that China’s things will become global.  304 stainless steel, widely used, can be steel plates, forgings, bolts and other materials.  ASME is the Standard of the American Society of Engineers, ASTM is the standard of the American Society of Materials, ANSI is the national standard of the United States, API is the standard of the American Petroleum Institute, for the specific material number to see the specific provisions in the corresponding standard number.  But the most important thing is that 304 is not the material in China’s national standard.  

Q4:What material A694 F52 equivalent to domestic？

A:Brand: F52

Standard: ASTM A694 Forgings for carbon and alloy steel flanges, fittings, valves and parts for high pressure transmission equipment

C: 0.26-0.265

Mn: the biggest 1.4

P: the biggest 0.03

S: the biggest 0.03

Si: 0.10 to 0.40

Minimum yield strength (0.2% variation) :52 (360) KSI(MPa)

Minimum tensile strength: 66 (455) SI(MPa)

Q5:What are parameters related A105 steel?

A:A105 is a low carbon steel forgings, similar to 20 steel. Its standard has two, one is the American standard “ASTM A105/A105M pipe components for carbon steel forgings”, the second is the Chinese standard “GB/T12228-2006 general valve carbon steel forgings technical conditions”.

Ingredients C: 0.35 or less Si: 0.35 Mn or less: 0.6 1.05 S: 0.050 or less P: 0.040 or less, Cu Ni acuities were 0.4 0.4 or less Mo 0.12 V 0.08 or less or less Cr 0.3 or less

The mechanical properties are between 20 forged steel and 16Mn forged steel.

Mechanical properties (Mpa)

Tensile strength :(σb) ≥485Mpa

Service strength (σs) ≥250Mpa

Elongation after (δ) ≥22%

Area reduction (ψ) ≥30%

Hardness HB187 or less

Q6:What is a350LF2 made of?

A:A350: Low temperature steel forgings: Brand steel Number: Lf1, Lf2, Lf3. A350LF2 is a material in the American standard, especially in low temperature environment pipe connection, forgings are made of A350LF2 material valves, flanges and pipe fittings.

A350 Chemical composition:

C: max0.30

Mn: 0.60-1.35

P: max0.035

S: max0.040

Si: 0.15-0.30

Ni: 0.40 Max

Cr: 0.30 Max

Mo: 0.12 maxB

Cu: 0.40 Max

Co: 0.02 Max

V: 0.08 Max

A350Lf2 Mechanical properties:

Tensile strength: 485-655mpa

Yield strength: 250MPa

Reduction of section: 30%

Hardness: less than 197HB

The replacement material of A350LF2 must not only meet the chemical composition and mechanical properties, but also pass the low temperature impact test. The chemical composition is roughly equivalent to 16Mn in Our country, but the scope of application of 16Mn is -29℃ in low temperature environment, while A350LF2 can be applied to -46℃ in low temperature environment.

The chemical composition of A350 has an important influence on the formation of crystal crack during welding. During welding, impurities such as S and P in the weld form eutectic with low melting point during crystallization. Among them, S has the greatest influence on the formation of crystallization crack, but its influence is related to the content of other elements in steel, such as Mn and S combine to form MnS and remove sulfur, thus inhibiting the harmful effect of S. Mn can also improve the properties, morphology and distribution of sulfide. Therefore, in order to prevent crystallization cracks, there are certain requirements for Mn/S value in weld metal.

Q7:What does Class 600# RF, A694gr.F70, ASME B16.47 stand for?

A:Class 600# refers to pressure level: 600 pounds

RF refers to the valve connection form for RF flange, namely flanged valve

A694 refers to the valve body material standard: ASTM A694 carbon and alloy steel pipe flanges, fittings, valves and forgings for high pressure transmission equipment

Gr.f70 material: chemical composition is similar to China’s No. 25 steel, but the minimum yield strength (0.2% variation), KSI(Mpa) : 70 (485)

ASME B16.47: This refers to ASME B16.47 large diameter pipe steel flanges on valves

Q8:What material is Q245b?

A:Q245b is a common carbon structural steel with a yield strength of 245 MPa, belonging to the semi-killed steel.

General carbon structural steel

Form: steel rod. The steel plate. The steel belt. Wire rod. forgings

Executive standard: EN10025 (1994)

This kind of steel is similar to the steel listed in GB/T700 and GB/T1591 in China. It is also carbon structural steel and low alloy structural steel used in engineering and structural steels. It is usually delivered without heat treatment. S275 is equivalent to Q275.

Q9:Round steel forging flaw detection standard GB6402 and JB4730, which standard is higher?

A:GB6402 standard is steel forgings ultrasonic detection method, is the national standard, and is specifically for steel forgings, JB4730-2005 standard is the machinery industry standard, JB4730. There are special ultrasonic standards in 3-2005 standards, which are general standards and general detection methods.

Q10:Is there any Q235B flange used? Do you have forgings for Q235B?

A：Q235B flange material is very common, small diameter general direct steel plate material, and then machined; Large diameter often using several sections of welding or cutting strip bending molding. General alloy steel shaft is often used forgings, and for very common Q235B material, but also flange parts, do not need to use forging, mechanical properties are enough, do not waste production costs.