Details of 15CrMoG alloy steel pipes commonly used in industrial projects

1. 15crmog high-pressure alloy steel pipe unit equipment: 5 LG20 finishing mills, 4 LG60 finishing mills, 3 LG80 finishing mills, 3 three-roller finishing mills (production range 12-219*1-30mm, tolerance +-0.025mm), 7 cold drawing machines (drawing machine stroke up to 12 meters, drawing force up to 350 tons), 2 high-precision vertical honing machines, 8 horizontal honing machines (inner diameter 30mm-800mm, wall thickness 2mm-100mm. Technical conditions: inner hole accuracy H7-H10. Inner hole roughness Ra≤0.63um, straightness ≤0.3mm/m. Steel grades are 20#, 45#, 16Mn, 27SiMn and some low-alloy steels. Standard GB8713-88)
2. 15crmog high-pressure alloy steel pipe production specifications: outer diameter 6-219mm* wall thickness 0.6-22mm
3. 15crmog high-pressure alloy steel pipe tolerance range: outer diameter, inner hole, wall thickness can be within 0.03mm
4. 15crmog high-pressure alloy steel pipe precision cutting: automatic pipe cutting machine precision cutting, cutting length 10mm-6000mm, length tolerance +-0.1mm
5. 15crmog high pressure alloy steel pipe material: 20#, 45#, 16mn, 27simn, 20Cr, 40cr, 15crmo, 20crmo, 35crmo, 42crmo, 15crmog, 12cr1movg, P91, T91
6. 15crmog high-pressure alloy steel pipe process flow: tube billet - inspection - peeling - inspection - heating - perforation - pickling passivation - grinding - lubrication and air drying - cold rolling - degreasing - cutting - inspection - marking - finished product packaging
15crmog high-pressure alloy steel pipe is a high-precision, high-brightness seamless steel pipe produced by cold drawing or cold rolling. Its inner and outer diameters can be accurate to within 0.2mm. While ensuring the same bending and torsional strength, it is light in weight, so it is widely used in the manufacture of precision mechanical parts and engineering structures. It is also commonly used to produce various conventional weapons, gun barrels, shells, bearings, etc.

First, the mechanical properties of 15crmog high-pressure alloy steel pipe
Tensile strength: σb ≥590MPa
Yield strength: σs ≥350MPa
Elongation: δ ≥17%
Sectional shrinkage: ψ ≥45%
Hardness: HB ≤195
Impact toughness: At room temperature, its impact absorption energy is ≥47J, and in high temperature environment, the impact toughness will also remain at a relatively high level.
High temperature strength: In a high temperature environment of 500℃~550℃, 15CrMoG alloy steel pipe can withstand a certain pressure, has good thermal strength, and its lasting strength and creep strength are also excellent.
Oxidation resistance: The addition of chromium enables it to form a dense chromium oxide film in a high temperature environment. This film can effectively prevent oxygen from further oxidizing the matrix of the steel pipe, thereby improving the oxidation resistance of the steel pipe.
Welding performance: The weldability is relatively poor. Due to the high content of carbon and other alloy elements, the hardening tendency is obvious. Appropriate preheating and slow cooling measures must be taken during welding, otherwise welding cracks are likely to occur.

Second, the physical properties of 15crmog high-pressure alloy steel pipe
Density: about 7.85g/cm³
Thermal conductivity: changes with the increase of temperature, about 38W/(m·K) at about 450℃
Linear expansion coefficient: about 12.5×10⁻⁶/℃
Elastic modulus: about 200GPa

Third, the production process of 15crmog high-pressure alloy steel pipe
The production process of 15CrMoG alloy steel pipe is relatively complicated, mainly including the following steps:
Raw material preparation: select high-quality carbon structural steel or alloy structural steel as raw materials, and go through smelting, ingot casting, and other processes to ensure that the chemical composition meets the standard requirements.
Hot rolling: The billet is heated to a certain temperature and then hot rolled. The hot rolling temperature is generally between 1000℃ and 1200℃. Through multiple rolling passes, the steel pipe reaches the required external dimensions and organizational properties. During the hot rolling process, the rolling temperature, rolling speed, and other parameters must be strictly controlled to ensure the quality of the steel pipe.
Normalizing: Hot-rolled steel pipes usually need to be normalized. The normalizing temperature is generally between 900℃ and 950℃. After a certain period of heat preservation, they are taken out of the furnace and air-cooled. The purpose of normalizing is to refine the grains and improve the comprehensive mechanical properties of the steel pipe.
Tempering: After normalizing, the steel pipe also needs to be tempered. The tempering temperature is generally between 700℃ and 750℃. After a certain period of heat preservation, they are taken out of the furnace and air-cooled. Tempering can eliminate the residual stress of the steel pipe and improve the toughness and plasticity of the steel pipe.
Nondestructive testing: Ultrasonic testing, X-ray testing, and other nondestructive testing are performed on the steel pipe to check whether there are defects such as cracks and inclusions inside the steel pipe to ensure that the quality of the steel pipe is qualified.
Finished product inspection: The size, shape, weight, etc. of the steel pipe are inspected to ensure that they meet the standard requirements.

Fourth, the purpose and application field of 15CrMoG high-pressure alloy steel pipe
15CrMoG alloy steel pipe is widely used in large-scale equipment with harsh use conditions and complex corrosive media such as petrochemical, coal conversion, nuclear power, steam turbine, cylinder, thermal power, etc. In petrochemical equipment, it is often used to manufacture high-temperature, high-pressure, corrosion-resistant pipes, pipe fittings and equipment, such as reactors, heat exchangers, pipelines, etc.; in nuclear power equipment, it can be used to manufacture coolant pipelines and steam generator pipelines of nuclear reactors; in fertilizer equipment, it can be used to manufacture high-temperature, high-pressure, corrosion-resistant synthetic ammonia pipelines, urea pipelines, etc.; in high-pressure boilers, 15CrMoG alloy steel pipes can be used to manufacture high-temperature headers, high-temperature superheaters, high-temperature reheaters and other components, which can withstand the high temperature, high pressure and complex corrosive environment when the boiler is running.