Chemical composition and uses of Q345B seamless steel pipe

Q355B Steel Pipe Circular pipes also have certain limitations. For example, in the case of plane bending, the strength of circular pipes is not as good as square pipes. According to traditional technology, it can be divided into straight seam arc welded steel pipe and straight seam submerged arc welded steel pipe.

General steel pipes, stainless steel pipes, high-pressure boiler steel pipes, medium-pressure boiler steel pipes, low-pressure boiler steel pipes, petroleum cracking steel pipes, alloy steel pipes, geological steel pipes and other steel pipes.

Long seam arc welded steel pipe and straight seam submerged arc welded steel pipe. When seamless pipes and straight-seam pipes have the same diameter and wall thickness, the pressure and robustness of seamless pipes are much greater than that of straight-seam pipes. To sum up, this is our summary of relevant experience on Q355B seamless steel pipe issues.

Q355 seamless steel pipe has an average carbon content of 0.42-0.50%, an average silicon content of 0.17-0.37%, an average manganese content of 0.50-0.80%, and an average sulfur content <=0.035% , average phosphorus content <=0.035%, average chromium content <=0.25%, average nickel content <=0.2545 steel contains about 0.45% carbon. After quenching and before tempering, Q355B steel has a hardness greater than HRC55 (up to HRC62) is qualified. The highest hardness for practical application is HRC55 (high frequency quenching HRC58).

Q345B seamless steel pipe consists of Q + number + quality grade symbol + deoxidation method symbol. Its steel number is prefixed with "Q", which represents the yield point of the steel. The following number represents the yield point value in MPa. For example, Q345 represents carbon structural steel I with a yield point (Rel) of 345 MPa.

Chemical composition of Q345B seamless steel pipe:

C: ≤0.20%,

Si≤0.50%,

Mn: ≤1.70 %,

P≤0.035%,

S: ≤0.035%,

Nb≤0.07%,

V: ≤0.15 %,

Ti≤0.20%,

Cr≤0.30%,

Ni: ≤0.50%,

Cu: ≤0.30 %,

N: ≤0.012%,

Mo: ≤0.10%

Yield strength:

Thickness ≤16mm: ≥ 345,

When the thickness is 16 to 40mm: ≥335,

When the thickness is 40 to 63mm: ≥325,

When the thickness is 63 to 80mm: ≥315,

When the thickness is 80 to 100mm: ≥305,

When the thickness is 100 to 150mm: ≥285,

When the thickness is 150 to 200mm: ≥275.

Tensile strength: between 450 and 630.

Elongation: greater than 17.

Impact test: Test temperature: 20℃: greater than 34.

Use of Q345B seamless pipe

1. Material characteristics: Q345B seamless pipe is made of high-quality low-alloy structural steel, which has high strength, good plasticity, good toughness and excellent welding performance. .

At the same time, the material has properties such as corrosion resistance, high temperature resistance, pressure resistance, and wear resistance, and can meet the needs of use in various complex environments.

In addition, Q345B seamless pipe also has good mechanical properties, such as good bending performance, high tensile strength, etc.

2. Application fields: Q345B seamless pipes are widely used in petrochemical, electric power, heating, automobiles, ships, construction and other fields.

In the petrochemical industry, Q345B seamless pipes can be used as pipelines for transporting oil, natural gas, and chemical fluids, and have good pressure resistance and corrosion resistance.

In the power industry, Q345B seamless pipes are used as load-bearing pipes for power transmission lines and can withstand the requirements of high-voltage power transmission.

In the construction industry, Q345B seamless pipes are widely used in the support of various building structures and the construction of pipeline systems.

3. Market prospects: As the country increases investment in infrastructure construction and improves environmental protection requirements, the market demand for Q345B seamless pipes shows a steady growth trend.

Especially in energy industries such as oil and natural gas, as well as in infrastructure construction fields such as heating and water supply, the demand for high-strength, high-pressure-resistant, and corrosion-resistant pipes is increasing.

At the same time, with technological progress and industrial upgrading, the quality and production technology of Q345B seamless pipes continue to improve, which will further expand its market share.

In short, Q345B seamless pipe, as a widely used steel pipe material, has excellent performance and broad application prospects, and has been widely used and promoted in various fields.

With the development of economy and advancement of technology, it is believed that Q345B seamless pipe will continue to show strong growth momentum in the future market.