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Tianjin lefin Industrial
TIANJIN LEFIN STEEL GROUP containing Tianjin lefin Industrial Co.,Ltd. 、Tianjin lefin steel import & export Co.,Ltd and Tianjin Shengqifeng International Trading Co., Ltd. -
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Steel Pipe Processing
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard -
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Guarantee Quality
Our steel pipes are suitable for oil, natural gas, shipbuilding, chemical industry, water conservancy, electrical, steel structure, construction and other related fields.
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Has rich experience in steel pipe processing, can be customized according to customer requirements according to the drawing and sample processing, assist in the development of new products.
fiji ASTM A572 GR.50 LSAW STEEL PIPE
Category:
Product Description
ASTM A572 GR.50 LSAW steel pipes, with their high strength and process reliability, have become the preferred material for heavy-duty projects, especially suitable for scenarios with strict requirements for safety and durability.
1. Overview of Main steel grades and differences
| Steel grade | Yield strength (ksi/MPa) | Tensile Strength (ksi/MPa) | Chemical Composition Characteristics | Typical Application scenarios |
| GR.42 | 42 (290) | 60 (415) | Low manganese, no microalloying elements | Lightweight structure, common pressure-bearing pipeline |
| GR.50 | 50 (345) | 65 (450) | Niobium/vanadium microalloy | High-pressure pipelines, Bridges, buildings |
| GR.60 | 60 (415) | 75 (520) | High manganese + niobium/vanadium reinforcement | Heavy-duty structures, deep-sea pipelines |
| GR.65 | 65 (450) | 80 (550) | High manganese + niobium/vanadium/titanium composite strengthening | Extreme high pressure and low temperature environment |
2. Detailed difference analysis
(1) Chemical composition
• GR.42:
Carbon (C) : ≤0.26%, Manganese (Mn) : ≤1.35%
No microalloys are added, resulting in a lower cost but limited strength.
• GR.50:
Carbon (C) : ≤0.23%, Manganese (Mn) : ≤1.35%
• Add niobium (Nb) or vanadium (V) to enhance strength through grain refinement.
• GR.60/GR.65:
Carbon (C) : ≤0.23%, Manganese (Mn) : ≤1.65%
It features a higher manganese content and is compounded with niobium, vanadium and titanium (Ti) to achieve a balance between high strength and toughness.
(2) Mechanical properties
• Strength enhancement:
The yield strength of GR.50 is approximately 19% higher than that of GR.42 (290→345 MPa), while that of GR.65 is another 30% higher than that of GR.50 (345→450 MPa).
• Elongation rate:
The elongation of high-strength steel grades (such as GR.60/65) is slightly lower (≥16%), but still meets the structural plasticity requirements.
• Low-temperature toughness:
Steel grades GR.50 and higher need to meet the impact test at -40℃, and GR.65 may have stricter requirements (such as -60℃).
(3) Processing and welding
• GR.42:
It has excellent welding performance and does not require complex preheating processes.
• GR.50-GR.65:
The welding heat input needs to be controlled, and the preheating temperature should be increased (for example, GR.65 requires preheating at 150-200℃) to prevent cold cracking.
The welding materials need to match the strength (such as AWS E10018-G electrodes).
(4) Cost and Economy
• Material cost: GR.65 > GR.60 > GR.50 > GR.42 (due to the increase in alloy content).
• Comprehensive cost: High-strength steel grade can reduce material usage (such as thinning the wall thickness), making it suitable for large-span or high-load scenarios.
3. Application scenario comparison
• GR.42:
Low-stress structures (warehouse supports, fences), low-pressure water pipes/air pipes.
• GR.50:
• Main oil and gas transportation lines, bridge supports, and high-rise building frames.
• GR.60:
Deep-sea oil and gas pipelines, heavy robotic arm structures, and buildings in earthquake-prone areas.
• GR.65:
Polar low-temperature pipelines, ultra-high pressure gas storage tanks, and pressure-resistant components for nuclear power plants.
4. Selection suggestions
• Priority GR.50: High cost performance, covering most engineering requirements.
• Conditions for choosing GR.60/65:
• The design load is extremely high or requires significant weight reduction (such as on offshore platforms).
• Low-temperature environments (such as Arctic pipelines) or strict fatigue resistance requirements.
• Use GR.42 with caution: Only for non-critical and low-stress scenarios.
5. Testing and Standards
• High-strength steel grade (GR.60/65) requires additional testing:
• Charpy V-notch impact test (low-temperature toughness).
Hardness test (to prevent weld embrittlement).
• Strict non-destructive testing (UT/RT) ratio (such as API 5L PSL2 requiring 100% testing).
Summary
ASTM A572 LSAW steel pipes achieve strength classification by adjusting the alloy composition. GR.50 is a universal high-strength choice, while GR.60/65 is targeted at extreme working conditions. The selection should balance the strength requirements, processing difficulty and cost, and strictly follow the welding and inspection specifications.
Address: Hengtai Road,Daqiuzhuang Town,Jinghai County,Tianjin,China
Mob: +8615122229899(whatspp)
Phone: +86 22 58171905
Fax: +86 22 58171902
E-mail:info@lefinsteel.com
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