GB/T 14291 Q235A/Q235B Welded Steel Tube for Mine Liquid Service with 4–1200 mm Diameter Range
Price:
USD 500-900 Tons
MOQ:
3 Tons
Delivery Time:
30 Work Days
Brand:
TORICH
Product Description
GB/T 14291 Q235 Welded Steel Tubes For Mine Liquid Service
Product Overview
GB/T 14291 Q235 welded steel tubes are straight-seam ERW carbon steel tubes specifically designed for mine liquid and auxiliary fluid service applications. These tubes are engineered for use in mine pressured-air lines, drainage systems, gas-drainage lines, and slurry transportation. Manufactured primarily from Q235A/Q235B mild steel, with optional higher-strength grades including Q295 and Q345 for projects requiring increased yield strength. GB/T 14291 comprehensively defines dimensions, shape, weight, technical requirements, test methods, inspection rules, packaging, marking, and quality certification for this specialized tube category.
Technical Specifications
| Parameter | Specification |
|---|---|
| Material | Carbon structural steel / low-alloy structural steel |
| Standard | GB/T 14291 Welded Steel Tubes for Mine Liquid Service |
| Steel Grade | Q235A, Q235B; optional Q295A/Q295B/Q345A/Q345B by order |
| Outside Diameter | 4-1200 mm commercial supply range |
| Wall Thickness | 0.3-200 mm commercial supply range |
| Length | 1-12 m customized; 4-12 m common supply range |
| OD Tolerance | D ≤ 48.3 mm: ±0.50 mm; 48.3 < D ≤ 273 mm: ±1%D; D > 273 mm: ±0.75%D |
| Wall Thickness Tolerance | ±10%S |
| Straightness | Commercially controlled for mine pipeline installation; stricter straightness can be agreed in purchase specification |
| Surface Condition | Black, oiled, varnished, painted, or galvanized by agreement |
| Heat Treatment | Normally supplied as-welded/as-rolled; heat treatment or stress relief only when specified |
Key Characteristics
- Q235A/Q235B pipe mechanical baseline under GB/T 14291: tensile strength not less than 375 MPa, lower yield strength not less than 235 MPa, elongation not less than 15% for D ≤ 168.3 mm and not less than 20% for D > 168.3 mm
- Precise dimensional control for mine pipe fitting: OD tolerance is ±0.50 mm for D ≤ 48.3 mm, ±1%D for 48.3 < D ≤ 273 mm, and ±0.75%D for D > 273 mm; wall thickness tolerance is ±10%S
- Comprehensive inspection aligned to mine-service risk: chemical composition checked by furnace, tensile testing by batch, with hydraulic testing, ultrasonic examination, and eddy-current flaw detection as standard inspection items
- Q235 mild carbon structural steel with density of approximately 7.85 g/cm³, commonly used without heat treatment where moderate strength, weldability, and formability are required
Quality Advantages
- Superior leakage control: Each pipe undergoes hydraulic-test control and weld-seam inspection according to agreed inspection plans, utilizing GB/T 241 hydrostatic testing, GB/T 18256 ultrasonic testing, or GB/T 7735 eddy-current testing as required
- Transparent tolerance specifications: We quote against declared GB/T 14291 tolerance bands and accommodate project-specific requirements including fixed length, beveled ends, coating thickness, marking format, and third-party inspection
- Complete material traceability: Comprehensive material records based on heat analysis, furnace identification, batch tensile testing, and quality certificate requirements, referencing GB/T 700 for carbon structural steels and GB/T 1591 for high-strength low-alloy structural steels
International Standards Compliance
| Standard System | Applicable Standard | Description |
|---|---|---|
| GB | GB/T 14291 | Primary standard for welded steel tubes used in mine liquid service |
| GB | GB/T 700 | Material reference for Q235 carbon structural steel |
| GB | GB/T 1591 | Material reference for Q295/Q345 low-alloy structural steel |
| ASTM | ASTM A53/A53M | Comparable standard for black or hot-dip galvanized welded/seamless steel pipe |
| EN | EN 10217-1 | Welded non-alloy steel tubes for pressure purposes with specified room-temperature properties |
| JIS | JIS G 3452 | Carbon steel pipe for ordinary piping at comparatively low working pressure |
| GOST | GOST 10705 | Electric-welded steel pipes for pipelines, structures, and general-purpose products |
Primary Application
Underground mine slurry drainage pipeline systems for transporting water mixed with coal fines or mineral particles from working areas to drainage sumps.
Chemical Composition
| Grade | Standard | C | Si | Mn | P | S | Other Elements |
|---|---|---|---|---|---|---|---|
| Q235A | GB/T 700 | ≤0.22 | ≤0.35 | ≤1.40 | ≤0.045 | ≤0.050 | Rimmed or killed |
| Q235B | GB/T 700 | ≤0.20 | ≤0.35 | ≤1.40 | ≤0.045 | ≤0.045 | Rimmed or killed |
| Q295A | GB/T 1591-1994 | ≤0.16 | ≤0.55 | 0.80-1.50 | ≤0.045 | ≤0.045 | Ti 0.02-0.20; V 0.02-0.15; Nb 0.015-0.060; Cr/Ni/Cu ≤0.30 each |
| Q295B | GB/T 1591-1994 | ≤0.16 | ≤0.55 | 0.80-1.50 | ≤0.040 | ≤0.040 | Ti 0.02-0.20; V 0.02-0.15; Nb 0.015-0.060; Cr/Ni/Cu ≤0.30 each |
| Q345A | GB/T 1591-1994 | ≤0.20 | ≤0.55 | 1.00-1.60 | ≤0.045 | ≤0.045 | Ti 0.02-0.20; V 0.02-0.15; Nb 0.015-0.060; Cr/Ni/Cu ≤0.30 each |
Mechanical Properties
| Grade | Tensile Strength Rm, MPa min. | Lower Yield Strength ReL, MPa min. | Elongation A, % min. D ≤ 168.3 mm | Elongation A, % min. D > 168.3 mm |
|---|---|---|---|---|
| Q235A | 375 | 235 | 15 | 20 |
| Q235B | 375 | 235 | 15 | 20 |
| Q295A | 390 | 295 | 13 | 18 |
| Q295B | 390 | 295 | 13 | 18 |
| Q345A | 470 | 345 | 13 | 18 |
Product Gallery
Frequently Asked Questions
Q: Are you trading company or manufacturer?
A: We are a manufacturer, but we can also handle trading operations.
Q: How long is your delivery time?
A: Generally speaking, delivery time is 10-15 days if the goods are in stock, or 30-40 days if the goods are not in stock, depending on the order quantity.
Q: Do you provide samples? Is it free or extra?
A: Yes, we offer samples free of charge, but customers need to pay the freight costs.
Q: What is your terms of payment?
A: Payment terms: For orders ≤2000 USD, 100% payment in advance. For orders ≥2000 USD, 30% T/T payment in advance, with balance due before shipment.
If you have any other questions, please feel free to contact us.
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Company
TORICH INTERNATIONAL LIMITED
Location
Suite 1604-3, Hongan Plaza, #258 Die Yuan Road, Yinzhou District, Ningbo City, China
Contact Person
Richard SHEN