🟦 Product Overview

ERW Rectangular Pipe is produced by forming steel strip into a rectangular shape and welding the seam using high‑frequency resistance welding (HFW). It is widely used in:

• Structural engineering
• Construction frameworks
• Mechanical fabrication
• Furniture manufacturing
• Automotive components
• General engineering applications

ERW rectangular tubes offer:

• High dimensional accuracy
• Smooth internal and external surfaces
• Uniform wall thickness
• Excellent weldability and formability

They are one of the most commonly used structural hollow sections for modern construction and mechanical systems.

🟦 Standards

• ASTM A500 (Grade A/B/C)
• EN 10219 (S235 / S275 / S355)
• GB/T 6728 (Cold‑formed structural tubes)
• BS 1387
• ASTM A53 (for non‑critical applications)

🟦 Grades

• Q195 / Q215 / Q235
• Q345 (high strength)
• S235 / S275 / S355
• ASTM A500 Grade A/B/C

🟦 Product Specifications & Available Sizes

Outer Size (Height × Width)

• 10×20 mm to 400×600 mm

Wall Thickness (WT)

• 0.8–20 mm

Length

• 6 m / 12 m / custom

End Types

• Plain End
• Beveled End

Surface Options

• Black
• Pre‑galvanized
• Hot‑dip galvanized
• Oiled
• Varnish coated

Rectangular Pipe	10*20-75*45	0.24-0.31
	10*20-75*45	0.33-0.38
	10*20-75*45	0.40-2.0
	10*20-75*45	0.24-0.31
	10*20-75*45	0.33-0.38
	10*20-75*45	0.40-2.0

🟦 Chemical Composition

(Example: Q235 / S235)

Q235

Element	Content (%)
C	≤ 0.22
Mn	≤ 1.40
Si	≤ 0.35
P	≤ 0.045
S	≤ 0.045

S235

Element	Content (%)
C	≤ 0.22
Mn	≤ 1.60
Si	≤ 0.55
P	≤ 0.040
S	≤ 0.040

🟦 Mechanical Properties

Q235

Property	Requirement
Tensile Strength	375–500 MPa
Yield Strength	≥ 235 MPa
Elongation	≥ 26%

S235

Property	Requirement
Tensile Strength	360–510 MPa
Yield Strength	≥ 235 MPa
Elongation	≥ 26%

🟦 Physical Properties

Property	Value
Density	7.85 g/cm³
Thermal Conductivity	45–60 W/m·K
Magnetic	Yes

🟦 Manufacturing Processes

• High‑frequency ERW welding
• Sizing & shaping
• Straightening
• Annealing (optional)
• Galvanizing (optional)
• Hydrostatic testing
• Eddy current testing

🟦 Primary Industry Usage

• Structural frameworks
• Construction and building systems
• Mechanical fabrication
• Furniture manufacturing
• Automotive components
• General engineering applications

🟦 Why Use ERW Rectangular Pipe

• High dimensional accuracy
• Excellent weldability and formability
• Smooth surface for fabrication
• Cost‑effective structural solution
• Available in black and galvanized finishes

🟦 Why Choose WelSteels

• Full size range of ERW rectangular tubes
• Black, pre‑galvanized, and hot‑dip galvanized options
• MTC 3.1 + third‑party inspection
• Export‑grade packaging & loading supervision
• Competitive pricing for construction and engineering projects

International Standards

China	America	Germany	Japan	France	Britain	International
GB3077	AlSI	DIN	JIS	NE	BS	ISO
20Mn2	13201221	20Mn5	SMn21	20M5	150M19	–
30Mn2	1330	30Mn5	SMn24	32M5	150M28	–
35Mn2	1335	36Mn5	SMnl	35M5	150M36	–
40Mn2	13401341	–	SMn2	40M5	–	–
45Mn2	1345	46Mn7	SMn3	45M5	–	–
50Mn2	1052	50Mn7	–	55M5	–	–
20MnV	–	20MnV6	–		–	–
30Mn2MoW	–	—	–		–	–
27SiMn	–	27MnSi5	–		–	–
35SiMn	–	37MnSi5	–	38MS5	–	–
42SiMn	–	38MnSi446MnSi4	–	38MS5	–	–
20SiMn2MoV	–	–	–	–	–	–
25SiMn2MoV	–	–	–	–	–	–
37SiMn2MoV	–	–	–	–	–	–
40B	14B35	35B2	–	–	–	–
45B	50B46H	45B2	–	–	–	–
50B	14B50	–	–	–	–	–
4OM∏B	15B41	–	–	–	–	–
45MnB	15B4850B44	–	–	–	–	–
20Mn2B	–	–	–	–	–	–
20MnMoB	80B20	–	–	–	–	–
15MnVB	–	–	–	–	–	–
–	–	–	–	–	–	–
–	–	–	–	–	–	–
20MnVB	–	–	–	–	–	–
40MnVB	–	–	–	–	–	–
20MnTiB	–	–	–	–	–	–
25MnTiBRE	–	–	–	–	–	–
2OSiMnVB	–	–	–	–	–	–
15Cr	50155115	15Cr3	SCr21	12C3	523A14523M15	–
15CrA	–	–	–	–	–	–
20Cr	5120	20Cr4	SCr22	18C318C4	527A19527M20	683/1120Cr420CrS4
30Cr	5130	28Cr4	SCr2	28C432C4	530A30530A32	–
35Cr	5135	34Cr437Cr4	SCr3	38C4	530A36	683/83、 3a、 3b
40Cr	5140	38Cr441Cr4	SCr4	42C4	530A40530M40	683/14、 4a^ 4b
45Cr	5145	42Cr4	SCR5	45C4	–	–
50Cr	51505152	–	–	50C4	En48	–
38CrSi	–	–	–	–	–	–
12CrMo	4119	13CrMo44	–	12CD415CD2	–	–
15CrMo	ASTMA-387Gr. B	15CrMo516CrMo44	SCM21	15CD4. 05	BS1653	–
20CrMo	4118	20CrMo522CrMo4	SCM22	18CD420CD4	CDS 12CDSllO	–
30CrMo	4130	25CrMo4	SCM2	30CD4	CDS 13	–
30CrMoA	–	32CrMol23ICRMo12	–	–	–	–
35CrMo	41354137	34CrMo435CrMo4	SCM3	35CD4	78A37	683/1C35eaC35eb
42CrMo	41404142	41CrMo442CrMo4	SCM4	40CD442CD4	708M40708A42709M40	683/13
12CrMoV	–	–	–	–	–	–
35CrMoV	–	35CrMoV5	–	–	–	–
12CrlMoV	–	13CrMoV4.2	–	–	–	–
25Cr2MoVA	–	24CrMoV5.5	–	–	–	–
25Cr2MolVA	–	–	–	–	–	–
20CR3MoWVA	–	21CrVMoW12	–	–	–	–
38CrMoΛl	6370 (ΛMS)	34CrAlMo541CrAlMo7	SACM645	40CAD6.12	905M39	683/1041CrAlMo74
20CrV	6120	22CrV4	–	22CrV4	–	–
40CrV	6140	42CrV	–	42CrV4	–	–
50CrVA	6150	50CrV4	SUPlO	50CV4	735A50	–
15CrMn	–	16MnCr5	–	16MC5	–	–
20CrMn	5120	20MnCr5	SMC21	20MC5	–	–
40CrMn	5140	–	SMC3	–	–	–
20CrMnSi	–	–		–	–	–
25CrMnSi	–	–	SMKl	–	–	–
30CrMnSi	–	–	–	–	–	–
30CrMnSiA	–	–	–	–	–	–
35CrMnSiA	–	–	SMK2	–	–	–
20CrMnMo	4119	20CrMo5	SCM23	–	–	–
40CrMnMo	4140	–	–	–	–	–
20CrMnTi	–	–	SMK22	–	–	–
30CrMnTi	–	30MnCrTi4	–	–	–	–
20CrNi	3120	20NiCr6	–	20NC6	637A16637M17	–
40CrNi	3140	46NiCr6	SNCl	35NC6	640A35640M40	–
45CrNi	3145	45NiCr6	–	–	–	–
50CrNi	3150	–	–	–	–	–
12CrNi2	3115	14NiCrlO	SNC21	IONCll14NC11	–	–
12CrNi3	3310	13NiCrl2	SNC22	10NC1214NC12	655A12655M13	–
20CrNi3	–	22NiCrl4	–	20NC11	–	–
30CrNi3	–	28NiCrlO31NiCrl4	SNC2	30NC1130NC12	–	–
37CrNi3	–	35NiCrl8	SNC3	35NC15	–	–
12Cr2Ni4	E3310	14NiCrl8	–	12NC15	–	–
20Cr2Ni4	E3316	22NiCrl4	–	20NC14	659A15659M15	–
20CrNiMo	8620    8720	20NiCrMo221NiCrMo2	–	20NCD2	805A20805M20	–
40CrNiMoA	4340     9840	36NiCrMo440NiCrMo6	SNCM8	35NCD540NCD3	817M40816M40	–
45CrNiMoVA	4437	–	SNCM9	–	–	–
18Cr2Ni4WA
25Cr2Ni4WA