SA106B seamless steel pipe

ASTM A106 Grade B seamless steel pipe is a cornerstone of high-temperature pressure conveyance systems across global industries. This article provides a detailed overview of its specification, chemical and mechanical properties, manufacturing process, key applications, and the advantages that make it a preferred choice for critical service.

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Detailed Description

ASTM A106 is a standard specification from ASTM International (formerly the American Society for Testing and Materials) for seamless carbon steel pipe designed for high-temperature service. It is predominantly used in pipelines and pressure vessels where operating conditions involve elevated temperatures. The standard covers three grades: A, B, and C, with Grade B being the most commonly specified due to its optimal balance of strength, ductility, and cost-effectiveness. This pipe is intended for bending, flanging, and other coiling operations, making it exceptionally versatile.

Dimensional tolerance:

Pipe types	Outer-caliber（D）		Thickness（S）
	Pipe outer-caliber(mm)	Allowable warp(mm)	Pipe thickness(mm)	Allowable warp(mm)
Hot-rolled pipes	＞219～457	±1.0％	≤20	－10％，＋12.5％
			＞20～40	－10％，＋10％
	＞457～1066	±0.9％	＞40～70	－7％，＋9％
			＞70～120	－6％，＋8％

Mechanical Properties:

Standards	Steel pipes No.	Tensile strength（MPa）	Bend strength（MPa）	Elongation（％）	Impact energy（J）	Hardness
GB3087	10	335～475	≥195	≥24		/
GB3087	20	410～550	≥245	≥20		/
GB5310	20G	410～550	≥245	≥24	≥35	/
	20MnG	≥415	≥240	≥22	≥35	/
	25MnG	≥485	≥275	≥20	≥35	/
	15CrMoG	440～640	≥235	≥21	≥35	/
	12Cr2MoG	450～600	≥280	≥20	≥35	/
	12Cr1MoVG	470～640	≥255	≥21	≥35	/
	10Cr9Mo1VNb	≥585	≥415	≥20	≥35	/
ASME SA106	SA106B	≥415	≥240	≥22	≥35	/
ASME SA106	SA106C	≥485	≥275	≥20	≥35	/
ASME SA333	SA333Ⅰ级	≥380	≥205	≥28	－45≥18	/
ASME SA333	ASME SA335	SA335 P11	≥415	≥205	≥22	≥35	≤163HB
SA335 P12		≥415	≥220	≥22	≥35	≤163HB
SA335 P22		≥415	≥205	≥22	≥35	≤163HB
SA335 P5		≥415	≥205	≥22	≥35	≤187HB
SA335 P91		585～760	≥415	≥20	≥35	≤250HB
SA335 P92		≥620	≥440	≥20	≥35	250HB
DIN17175	ST45.8/Ⅲ	410～530	≥255	≥21	≥27(DVM)	/
	15Mo3	450～600	≥270	≥22	≥34(DVM)	/
	13CrMo44	440～590	≥290	≥22	≥34(DVM)	/
	10CrMo910	480～630	≥280	≥20	≥34(DVM)	/
EN10216-2	15NiCuMoNb5-6-4 (WB36)	610～780	≥440	≥19	≥40	/

Chemical composition:

Standards

Steel pipes No.

Chemical composition（%）

GB3087

0.07～0.13

0.17～0.37

0.38～0.65

≤0.030

0.3～0.65

≤0.25

≤0.30

0.17～0.23

0.17～0.37

0.38～0.65

≤0.030

0.3～0.65

≤0.25

≤0.30

GB5310

20G

0.17～0.24

0.17～0.37

0.35～0.65

≤0.030

≤0.25

≤0.15

≤0.20

≤0.25

≤0.08

20MnG

0.17～0.25

0.17～0.37

0.70～1.00

≤0.030

≤0.25

≤0.15

≤0.20

≤0.25

≤0.08

25MnG

0.23～0.27

0.17～0.37

0.70～1.00

≤0.030

≤0.25

≤0.15

≤0.20

≤0.25

≤0.08

15CrMo

0.12～0.18

0.17～0.37

0.40～0.70

≤0.030

0.80～1.10

0.40～0.55

≤0.20

≤0.30

12Cr2MoG

0.08～0.15

≤0.50

0.40～0.70

≤0.030

2.00～2.50

0.90～1.20

≤0.20

≤0.30

12Cr1MoV

0.08～0.15

0.17～0.37

0.40～0.70

≤0.030

0.90～1.20

0.25～0.35

≤0.20

≤0.30

0.15～0.30

10Cr9Mo1VNb

0.08～0.12

0.20～0.50

0.30～0.60

≤0.020

≤0.010

8.00～9.50

0.85～1.05

≤0.20

≤0.40

0.18～0.25

≤0.015

0.06～0.10

0.03～0.07

ASME SA106

SA106B

0.17～0.25

≥0.1

0.70～1.00

≤0.030

SA106C

0.23～0.27

≥0.1

0.70～1.00

≤0.030

ASME SA333

SA333Ⅰ

0.09～0.12

0.7～1.00

≤0.020

≤0.010

SA333Ⅵ

0.09～0.12

≥0.1

0.9～1.10

≤0.020

≤0.010

ASME SA335

SA335 P11

0.05～0.15

0.50～1.0

0.30～0.60

≤0.030

1.00～1.50

0.50～1.00

SA335 P12

0.05～0.15

≤0.50

0.30～0.61

≤0.030

0.80～1.25

0.44～0.65

SA335 P22

0.05～0.15

≤0.50

0.30～0.60

≤0.030

1.90～2.60

0.87～1.13

SA335 P5

≤0.15

≤0.50

0.30～0.60

≤0.030

4.00/
6.00

0.45/
0.65

SA335 P91

0.08～0.12

0.20～0.50

0.30～0.60

≤0.020

≤0.010

8.00～9.50

0.85～1.05

≤0.40

0.18～0.25

≤0.015

0.06～0.10

0.03～0.07

SA335 P92

0.07～0.13

≤0.50

0.30～0.60

≤0.020

≤0.010

8.50～9.50

0.30～0.60

≤0.40

0.15～0.25

≤0.015

1.50～2.00

0.04～0.09

0.03～0.07

DIN 17175

ST45.8/Ⅲ

≤0.21

0.10～0.35

0.40～1.20

≤0.040

≤0.30

15Mo3

0.12～0.20

0.10～0.35

0.40～0.80

≤0.035

0.25～0.35

13CrMo44

0.10～0.18

0.10～0.35

0.40～0.70

≤0.035

0.70～1.10

0.45～0.65

10CrMo910

0.08～0.15

≤0.50

0.30～0.70

≤0.025

≤0.020

2.00～2.50

0.90～1.10

≤0.30

≤0.015

EN1021 6-2

15NiCuMoNb5-6-4 (WB36)

≤0.17

0.25～0.50

0.80～1.20

≤0.025

≤0.020

≤0.30

0.25～0.50

0.50～0.80

1.00～1.30

≤0.05

0.015～0.045

Chemical Composition

The performance of A106B pipe is fundamentally dictated by its chemical composition, which is strictly controlled by the ASTM A106 standard. Key elements include:

Carbon (C): 0.30% max. Provides strength and hardness.

Manganese (Mn): 0.29 – 1.06%. Enhances strength and hardenability.

Phosphorus (P): 0.035% max. Impurity that reduces ductility and toughness.

Sulfur (S): 0.035% max. Impurity that causes brittleness.

Silicon (Si): 0.10% min. Adds strength and deoxidizes the steel.

The controlled low levels of impurities (S and P) and the balance of strengthening elements ensure reliable performance under stress and high heat.

Mechanical Properties

A106 Grade B pipe must meet minimum mechanical property requirements, which are verified through standardized testing:

Tensile Strength: 415 MPa (60,200 psi) minimum.

Yield Strength: 240 MPa (35,000 psi) minimum.

Elongation: The minimum elongation in 2 inches is a function of the pipe wall thickness but is typically around 20-30%, indicating good ductility and the ability to deform without fracturing.

These properties ensure the pipe can withstand the internal pressures and mechanical loads encountered in service.

Manufacturing Process

The "seamless" designation is crucial. These pipes are manufactured without a welded seam through a process that begins with a solid cylindrical steel billet. The billet is heated to a high temperature and then pierced through the center with a mandrel to create a hollow shell. This shell is subsequently elongated and rolled over a mandrel and stretched to achieve the desired diameter, wall thickness, and length. This homogeneous structure provides uniform strength around the entire circumference, eliminating the weak point that a weld seam can represent in high-pressure applications. The final pipes are then heat-treated (normalized) to refine the grain structure and enhance mechanical properties.