P690QL1 is a premium high-strength quenched and tempered alloy structural steel that belongs to the European standard EN 10025-6 series. It is specially formulated with precise alloying elements to deliver excellent toughness, superior weldability, and reliable corrosion resistance, making it an ideal material for heavy machinery manufacturing, large-scale construction projects, and offshore engineering structures that demand exceptional load-bearing capacity and long-term durability even in harsh working environments.
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P690QL1 Chemical Composition |
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Grade |
The Element Max (%) |
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C |
Si |
Mn |
P |
S |
N |
B |
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P690QL1 |
0.20 |
0.80 |
1.70 |
0.020 |
0.010 |
0.015 |
0.005 |
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Mo |
Cu |
Nb |
Ni |
Ti |
V |
Cr |
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0.70 |
0.3 |
0.06 |
2.50 |
0.05 |
0.12 |
1.50 |
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Grade |
P690QL1 Mechanical Property |
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Thickness |
Yield |
Tensile |
Elongation |
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P690QL1 |
mm |
Min Mpa |
Mpa |
Min % |
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6-50 |
690 |
770-940 |
14% |
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50-100 |
670 |
770-940 |
14% |
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100-150 |
630 |
720-900 |
14% |
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P690QL1 Processing Flow
Smelting and Casting:
Raw materials are smelted in an electric arc furnace or converter, with strict control of chemical composition (e.g., C, Si, Mn, Cr, Ni) to meet EN 10028-6 standards. The molten steel is refined and then cast into slabs via continuous casting to ensure uniform internal structure and avoid defects like segregation.
Controlled Rolling:
Slabs are heated to 1100-1250°C for homogenization, then rolled by multi-pass controlled rolling. Rolling temperature and speed are precisely adjusted to refine grain size and improve mechanical properties.
Quenching and Tempering:
After rolling, the steel plate is quenched (heated to austenitization temperature, then rapidly cooled with water/oil) to form a martensitic structure. It is then tempered at 550-650°C to relieve residual stress, enhance toughness, and achieve the desired strength-toughness balance.
Surface Treatment and Cutting:
The plate undergoes shot blasting or pickling to remove oxide scale. It is then cut into specified sizes via flame cutting, plasma cutting, or shearing, with edge trimming to ensure dimensional accuracy.
Quality Inspection:
Final inspections include ultrasonic testing (for internal defects), mechanical property testing (tensile, impact, hardness), and chemical composition analysis to confirm compliance with standards.
applications
Petrochemical and Chemical Industry
P690QL1 is widely used in the fabrication of pressure vessels, reactors, and storage tanks. These components operate under high pressure, high temperature, and corrosive conditions, and the steel's high yield strength, good toughness, and resistance to hydrogen-induced cracking ensure reliable performance and long service life.
Power Generation Sector
The steel is commonly applied in power plant boilers, including boiler drums, headers, and heat exchanger components. Its ability to withstand elevated pressures and temperatures, combined with excellent weldability, makes it suitable for critical power equipment that requires high structural integrity.
Cryogenic Applications
Due to its good low-temperature toughness (down to -40°C), P690QL1 is used in LNG storage tanks, cryogenic separators, and other equipment operating at extremely low temperatures. Its fine-grained microstructure ensures resistance to brittle fracture under cold conditions.
Offshore and Marine Engineering
P690QL1 is extensively employed in offshore platforms, subsea pipelines, and ship structures. These applications demand high strength, fatigue resistance, and corrosion resistance, all of which are provided by the steel's quenched and tempered microstructure and controlled chemical composition.
Nuclear Power Industry
The steel is used for key components in nuclear power plants where safety and reliability are paramount. Its consistent mechanical properties, excellent weldability, and ability to maintain performance under high stress make it suitable for reactor pressure vessels and related structures.
Heavy Machinery and Construction
P690QL1 is also utilized in heavy machinery, such as crane booms, hydraulic supports, and large structural components, where high strength and good formability are required to reduce weight while maintaining structural stability.
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We are fully dedicated to our customers. If it will not possible to meet your requirements after examining all options, we will not mislead you by making false promises which will create good customer relations.
If you have project requirements for p690ql1, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
What heat treatment process does P690QL1 undergo?
P690QL1 undergoes quenching and tempering heat treatment. Quenching improves hardness and strength, while tempering reduces brittleness and improves toughness, making the steel have balanced mechanical properties.
Is P690QL1 easy to weld?
Yes, P690QL1 has good weldability. Proper preheating (usually 80-150℃) and post-weld heat treatment can avoid weld cracks and ensure the strength and toughness of the weld joint.
Can P690QL1 be used in low-temperature environments?
Yes, P690QL1 is suitable for low-temperature environments. Its good low-temperature toughness ensures that it will not become brittle or crack when working at temperatures as low as -20℃, adapting to cold area projects.
What is the hardness of P690QL1?
The hardness of P690QL1 (HB) is generally between 220 and 280. This hardness range balances wear resistance and machinability, making it easy to cut, drill and other processing operations.
What is the density of P690QL1?
The density of P690QL1 is about 7.85 g/cm³, the same as ordinary carbon steel. This density value is important for weight calculation and structural design in engineering projects.
What is the melting point of P690QL1?
The melting point of P690QL1 is between 1450℃ and 1500℃, similar to other alloy structural steels. This parameter is crucial for welding, casting and other thermal processing operations.
Does P690QL1 have corrosion resistance?
P690QL1 has certain natural corrosion resistance due to its alloy composition. For harsh corrosion environments (such as offshore, chemical), additional anti-corrosion treatments (painting, galvanizing) are recommended to extend service life.
What standards does P690QL1 comply with?
P690QL1 mainly complies with the European standard EN 10025-6, which specifies the technical requirements for high-strength quenched and tempered structural steels, including chemical composition, mechanical properties and test methods.
What is the difference between P690QL1 and P690Q?
The main difference lies in impact toughness requirements. P690QL1 has higher low-temperature impact toughness than P690Q, with a specified test temperature of -20℃ (lower than P690Q), suitable for harsher low-temperature environments.
What are the common applications of P690QL1?
P690QL1 is commonly used in manufacturing heavy machinery parts, construction machinery (such as excavator arms), offshore platforms, bridge supports and other structures that require high strength and durability.