20G Seamless Pipe is a high-quality carbon steel pipe designed for excellent strength, toughness, and corrosion resistance in low and medium-pressure boiler applications. Conforming to the Chinese GB/T 5310-2017 standard, this pipe is composed of 0.17-0.23% carbon and 0.35-0.65% manganese, making it ideal for boiler pipeline protection in power plants, steam pipelines, and industrial piping systems operating at temperatures up to 450°C. Its seamless construction ensures superior durability and reliability under moderate pressure conditions.

The 20G Seamless Pipe is manufactured through hot-rolling or cold-drawing processes, typically delivered in a normalized or normalized-and-tempered state to optimize mechanical properties. The manganese content enhances strength and toughness, while the low carbon content ensures good weldability and formability, making it suitable for boiler pipeline protection in economizers, water walls, and low-pressure superheaters. Available in sizes from 10mm to 1200mm OD, with wall thicknesses from 2mm to 100mm, and lengths up to 12 meters or customized, it meets diverse project requirements.

The Seamless Carbon Steel Pipes undergo rigorous testing, including tensile, flattening, flaring, and hydrostatic tests, to ensure compliance with GB/T 5310 standards. With a tensile strength of 410-550 MPa and a minimum yield strength of 245 MPa, the 20G pipe offers reliable resistance to mechanical stress and moderate corrosion, ideal for handling steam and water in boiler systems. Surface treatments such as black varnish, galvanizing, or 3LPE coatings enhance corrosion resistance, while plain or beveled ends facilitate seamless integration into industrial piping systems.

Compared to alloy steel grades like 15CrMoG or 16Mn (Q345), the 20G Seamless Pipe has lower alloy content, making it more cost-effective for applications not requiring high-temperature or high-pressure resistance. Unlike 12Cr1MoVG, which is optimized for creep resistance at 580°C, 20G is suited for lower-temperature boiler components (up to 450°C). Its excellent weldability (carbon equivalent ~0.38) requires minimal preheating, making it easier to fabricate than higher-alloy grades like ASTM A335 P11. This makes it a preferred choice for low-pressure boilers, heat exchangers, and general-purpose industrial piping.

Engineered to address challenges like pipeline wear, corrosion, and mechanical stress, the 20G Seamless Pipe delivers reliable performance in low and medium-pressure industrial systems. Its robust carbon steel composition and seamless construction make it a cost-effective choice for engineers seeking durable industrial piping solutions for boiler and structural applications, ensuring safety, longevity, and efficiency in carbon steel pipe applications.

Key Benefits

High Strength

Tensile strength of 410-550 MPa for reliable performance.

Corrosion Resistance

Coatings ensure durability in moderate environments.

Excellent Weldability

Low carbon content ensures easy welding with minimal preheating.

Seamless Durability

Uniform construction for reliable pressure applications.

Cost-Effective

Long lifespan reduces maintenance costs.

Versatile Applications

Ideal for boilers, heat exchangers, and industrial piping.

Comparison of 20G with Other Pipe Grades
Feature	20G	16Mn (Q345)	15CrMoG
Material Type	Carbon Steel	Low Alloy Steel	Alloy Steel
Carbon Content	0.17-0.23%	0.12-0.20%	0.12-0.18%
Manganese Content	0.35-0.65%	0.70-1.00%	0.40-0.70%
Chromium Content	≤0.25%	≤0.30%	0.80-1.10%
Temperature Range	Up to 450°C	Up to 350°C	Up to 550°C
Corrosion Resistance	Moderate (With coatings)	Moderate (With coatings)	Excellent (With coatings)
Applications	Low-Pressure Boilers, Pipelines	Pressure Vessels, Structures	Boilers, Petrochemical
Tensile Strength (MPa)	410-550	470-630	440-640
Yield Strength (MPa)	245 (min)	345 (min)	235 (min)
Key Advantage	Excellent weldability	High strength, weldability	Balanced high-temp strength

Wall Thickness (W.T.) Tolerance Specifications
W.T. (mm)	Diameter (D, mm)	Tolerance
	-	+15% (+0.48mm min)
	-	-10% (+0.32mm min)
3.5–20	-	+15%, -10%
>20	D	±10%
>20	D≥219	+12.5%, -10%

Pipe Dimensions (Diameter * Wall Thickness, mm)
Column 1	Column 2	Column 3	Column 4
83*13	127*10	168*20	245*27
83*14	127*17	168*32	245*32
89*16	133*16	180*21	273*27
95*9.2	133*16	180*22	273*30
95*10	133*22	180*25	273*36
95*15	140*18	180*40	299*30
102*14	146*14	194*21	325*30
114*9.2	152*17	203*26	377*35
114*10	159*16	219*22	-
114*19	159*21	219*25	-

Comparison: 20# vs 20G Seamless Steel Pipes

Application Scope

20#: General-purpose use in structural parts, fluid transport, low/medium pressure boilers.

20G: Specialized for high-pressure boilers, superheaters, heat exchangers and pressure vessels.

Chemical Composition

20#: Plain carbon steel with standard carbon and manganese content.

20G: Contains trace alloying elements for improved high-temperature and oxidation resistance.

Mechanical Properties

20#: Good ductility, plasticity, and strength; suitable for cold forming.

20G: Higher creep strength, excellent dimensional stability under stress and heat.

Weldability & Machinability

20#: Easy to weld and machine; best with arc and resistance welding.

20G: Requires more precise welding conditions due to critical service applications.

Thermal & Pressure Resistance

20#: Suitable for moderate pressure and temperature ranges.

20G: High-temperature and high-pressure resistant; ideal for steam and boiler systems.

Cost & Availability

20#: Widely available and lower in cost, suitable for general industries.

20G: Higher cost due to precise alloying and application-specific quality standards.

20G is a GB 5310-grade low-carbon steel seamless pipe designed for high-pressure boilers. It offers excellent heat transfer, high tensile strength, and good corrosion resistance :contentReference[oaicite:1]{index=1}.

Typical composition includes C 0.17–0.24%, Si 0.17–0.37%, Mn 0.35–1.00%, Cr ≤ 0.25%, Mo ≤ 0.15%, Ni ≤ 0.25%, V ≤ 0.08% :contentReference[oaicite:2]{index=2}.

Strength properties include yield ≥ 415 MPa, tensile ~240 MPa, and elongation ~22% :contentReference[oaicite:3]{index=3}.

Available in dozens of OD×WT combinations (e.g., 83×13 mm, 114×19 mm, 273×27 mm) as per GB5310. Outer diameter range typically 0.75″–20″; wall thickness from 2.6 mm up to 100 mm. Lengths up to 16 m; U-bending available :contentReference[oaicite:4]{index=4}.

Delivered in annealed, normalized, or normalized-and-tempered condition. Manufactured to GB standards (GB8162/8163/3087/5310, etc.) and tested via hydrostatic, flattening, flaring, and NDT inspections :contentReference[oaicite:5]{index=5}.

Commonly used in high-pressure boilers (superheater, reheater, waterwall tubes), heat exchangers, and petroleum refinery pipelines requiring heat transfer and strength :contentReference[oaicite:6]{index=6}.

Surface treated with oil-dip, varnish, passivation, phosphating, or shot blasting. Subjected to chemical, mechanical (tensile, hardness), dimensional, hydrostatic, and NDT inspections :contentReference[oaicite:7]{index=7}.

Compared to 20#, 20G contains stricter trace element controls and better heat resistance. 20G is specifically designed for high-pressure boiler service, while 20# is a general structural/fluid pipe for lower-pressure applications :contentReference[oaicite:8]{index=8}.

Element	Composition (%)
Carbon (C)	0.17-0.23
Silicon (Si)	0.17-0.37
Manganese (Mn)	0.35-0.65
Phosphorus (P)	≤0.035
Sulfur (S)	≤0.035
Chromium (Cr)	≤0.25
Nickel (Ni)	≤0.25
Copper (Cu)	≤0.25

Property	Value
Tensile Strength (MPa)	410-550
Yield Strength, min (MPa)	245
Elongation, min (%)	24
Impact Toughness (J)	≥27 (at 20°C)

20G Seamless Steel Pipe

20G Seamless Steel Pipe