Q235 Steel Pipe

Specification

Product Name	Q235 Carbon Steel Pipe
Material	Q235 (Equivalent to ASTM A53 Gr.B)
Standard	GB/T 700, GB/T 8162, GB/T 8163, ASTM A53
Section Shape	Round, Square, Rectangular
Structure Type	Seamless / ERW Welded
Technique	Hot Rolled / Cold Drawn
Surface Treatment	Black Painted / Anti-rust Oil / Galvanized
Outer Diameter	21.3 mm – 610 mm (0.84″ – 24″)
Wall Thickness	1.5 mm – 20 mm
Length	6m – 12m or Custom Length
Certificates	ISO 9001, CE, SGS
Packing	Standard seaworthy packing

Features

• Moderate Strength: A yield strength of 235MPa ensures it meets the requirements of most structural components.
• Low Cost and Easy Machining: Convenient to smelt, it is recognized in the engineering industry as the “king of cost-effectiveness,” and can be easily welded, stamped, cut, and threaded.
• Diverse Grades & Surface Treatments: Can be oiled, painted black, hot-dip galvanized, or spray-painted; Q235A/B/C/D grades are available to adapt to different temperatures and environments.
• High Customization: Supports various wall thicknesses from Sch20 to Sch80, lengths from 6-12 meters, welding processes, cross-sectional shapes, and end treatments are all customizable.

Application Areas

• Building Structures: Steel structural frames, supporting beams, and columns for buildings, factories, and residential buildings.
• Bridge Engineering: Bridge deck supports, safety railings, and bridge connections.
• Machinery Manufacturing: Parts for large factory equipment, transmission connecting rods, and equipment frames.
• Vehicles/Petrochemicals: Process piping, platform structures, vehicle chassis, and frame parts.
• Others: Agricultural greenhouse frames, foundation piles, steel pipe piles, and anchor bolts.

Chemical composition and mechanical properties

Chemical Composition

Grade	C	Si	Mn	S max	P max
Q235A	0.14–0.22%	≤0.30%	0.30–0.65%	0.050%	0.045%
Q235B	0.12–0.20%	≤0.30%	0.30–0.70%	0.045%	0.045%
Q235C	≤0.18%	≤0.30%	0.35–0.80%	0.040%	0.040%
Q235D	≤0.17%	≤0.30%	0.35–0.80%	0.035%	0.035%

Mechanical Properties

Steel thickness (mm)	Minimum yield strength σs (MPa)	Tensile strength σb (MPa)	Elongation δ5 (%)
≤16	≥235	370–500	≥26
>16–40	≥225	370–500	≥25
>40–60	≥215	370–500	≥24
>60–100	≥205	370–500	≥23
>100–150	≥195	370–500	≥22
>150	≥185	370–500	≥21

Impact toughness requirements

Grade	Test temperature	Impact energy (Akv)
Q235B	20°C	≥27J
Q235C	0°C	≥27J
Q235D	-20°C	≥27J
Q235A	No requirement	—

Q235 Comparison with International Standards

GB	ASTM	EN	JIS	KS	GOST
‌Q235A‌	ASTM A283M Gr.D	S235JR	SS400	SS400	St3sp
‌Q235B‌	ASTM A36	S235JR	SS400	SS400	St3ps
‌Q235C/D‌	ASTM A36 (must meet low-temperature impact requirements)	S235J2	SS400 (Impurities need to be controlled)	SS400 (Impurities need to be controlled)	St3kp-2/-3/-4

Q235B (ASTM A36 / S235JR) is the mainstream carbon steel pipe material.

What are the classifications of Q235 carbon steel pipes?

1. Classification by Structure

• Q235 Seamless Steel Pipe – No weld seam, made by piercing round steel, with good overall pressure resistance. Higher cost, less versatile than welded pipes
• Q235 Welded Steel Pipe – Mainly divided into two types: ERW straight seam welded pipes and spiral welded pipes.
  • Q235ERW Straight Seam Welded Pipe – Electric Resistance Welding, suitable for mass production, more precise dimensions, lower cost, made from hot-rolled coils.
  • Q235 Spiral Welded Pipe – Commonly used for large-diameter, high-pressure, long-distance transportation, made by double-sided submerged arc welding of steel strip, with a spiral weld seam.

2. Classification by Production Process

• Hot-rolled Q235 Steel Pipe – Formed at high temperature, larger dimensions, thicker walls.
• Cold-drawn/Cold-rolled Q235 Steel Pipe – Hot-rolled and then processed at room temperature, high precision, bright surface.

Classification by End/Wall Thickness

• End: Plain End, Threaded, Beveled End.
• Wall Thickness: Represented by Sch; the larger the number, the thicker the wall and the stronger the pressure resistance.

Classification by Cross-sectional Shape

They are divided into round tubes, square tubes, and rectangular tubes, which are suitable for fluid transportation, building frames, and load-bearing beams and columns, respectively.

Common Specifications Reference

Q235 round tube

Nominal size	OD	Sch	Weight (kg/m)
1/2″ (DN15)	21.3	2.8	1.28
3/4″ (DN20)	26.9	2.8	1.66
1″ (DN25)	33.7	3.2	2.41
1-1/4″ (DN32)	42.4	3.5	3.36
1-1/2″ (DN40)	48.3	3.5	3.87
2″ (DN50)	60.3	3.8	5.29

Q235 square tube

Dimensions (mm)	WT (mm)	Weight (kg/m)
20×20	1.5	0.87
30×30	2.0	1.76
40×40	2.5	2.94
50×50	3.0	4.43
60×60	3.5	6.21
80×80	4.0	9.55

Q235 rectangular tube

Dimensions (mm)	WT (mm)	Weight (kg/m)
40×20	2.0	1.76
50×25	2.5	2.67
60×40	3.0	4.24
80×40	3.0	5.37
100×50	3.5	7.81
120×60	4.0	10.93

Weight calculation formula

• Round tube weight = (outer diameter − wall thickness) × wall thickness × 0.02466.
• Square tube weight = 0.0314 × wall thickness × (side length − wall thickness).
• Rectangular tube weight = 0.0157 × wall thickness × (long side + short side − 2 × wall thickness).

Why Choose Glory Steel?

• High-quality raw materials: Using national standard Q235 hot-rolled/cold-rolled steel coils as the base material, providing Q235A/B/C/D grades.
• Complete specifications: Seamless pipes, ERW straight seam welded pipes, spiral welded pipes, and square/rectangular pipes are all produced. Black pipes, oil pipes, hot-dip galvanized pipes, and end treatments can all be processed according to requirements.
• Cost advantage: Own factory, OEM/ODM services, large-scale production, stable delivery time, and competitive prices.
• Factory direct supply: Annual production capacity of 100,000 tons, with a regular inventory of 3,000+ tons, supporting third-party inspection, and each batch comes with a material certificate.

Glory Steel factory, located in Tianjin, China, is an ISO 9001, ISO 14001, and CE certified factory with an annual output of 100,000 tons. We specialize in manufacturing Q195/Q235/Q345/Q355 carbon steel pipe, including both seamless and ERW-welded pipe. With our high-quality products and services, we export to over 120 countries.