15CrMoG Alloy Steel Seamless Tube/Pipe - Product Introduction
15CrMoG is a chromium-molybdenum (Cr-Mo) pearlitic heat-resistant alloy steel grade specified in the Chinese standard GB 5310 for seamless tubes used in high-pressure boilers and other high-temperature service applications.
Its primary characteristics are excellent long-term strength (creep strength) and good oxidation resistance at elevated temperatures (typically up to 550-580°C). It is a widely used material for superheater tubes, reheater tubes, and header pipes in power station boilers and petrochemical plants.
Key Features & Applications
Main Applications: High-pressure boiler superheater, reheater, economizer, header, and main steam pipe. Also used in heat exchangers and piping for the petrochemical industry.
Key Advantages:
Good comprehensive mechanical properties.
Excellent resistance to oxidation and scaling at high temperatures.
High creep strength and rupture strength under long-term exposure to high temperature and pressure.
Good weldability and formability.
Chemical Composition (GB 5310 Standard Requirement)
The following table shows the required chemical composition (in percentage by weight).
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.12 ~ 0.18 |
| Silicon (Si) | 0.17 ~ 0.37 |
| Manganese (Mn) | 0.40 ~ 0.70 |
| Chromium (Cr) | 0.80 ~ 1.10 |
| Molybdenum (Mo) | 0.45 ~ 0.60 |
| Phosphorus (P) | ≤ 0.025 |
| Sulfur (S) | ≤ 0.025 |
| Nickel (Ni) | ≤ 0.30 |
| Copper (Cu) | ≤ 0.20 |
Mechanical Properties (GB 5310 Standard Requirement after Normalizing & Tempering Heat Treatment)
The following table outlines the key mechanical properties.
| Property | Requirement | Notes |
|---|---|---|
| Tensile Strength (Rm) | ≥ 440 MPa | - |
| Yield Strength (Rp0.2) | ≥ 295 MPa | - |
| Elongation (A) | ≥ 22 % | - |
| Impact Energy (KV2) | ≥ 55 J | At room temperature |
| Hardness | ≤ 160 HBW | Or other equivalent scale |
Dimensional Specifications and Tolerances
15CrMoG pipes are manufactured as seamless tubes. Common specifications include:
Outer Diameter (OD): Typically from 16 mm to 630 mm or larger.
Wall Thickness (WT): Typically from 2 mm to 80 mm.
Length: Typically 6 meters to 12 meters, or random lengths as per agreement.
Dimensional tolerances comply with GB 5310, which are generally similar to international standards like EN 10216 or ASTM A213. Common tolerances are:
OD Tolerance: Usually ±1.0% or specific values based on diameter and manufacturing method.
WT Tolerance: Typically in the range of ±10% to -10% / +12.5%, depending on thickness.
Comparable International Grades
15CrMoG is functionally equivalent to several grades in other international standards. Note: The chemical composition ranges are not identical, and substitution requires careful evaluation by an engineer.
| Standard | Grade | Common Name |
|---|---|---|
| ASTM/ASME (USA) | A213 T11 / A335 P11 | Grade T/P11 |
| DIN/EN (Europe) | 13CrMo4-5 (EN 10216-2) | 1.7335 |
| JIS (Japan) | STBA 22 / STPA 22 | - |
Summary Table of 15CrMoG Parameters
| Category | Details |
|---|---|
| Chinese Standard | GB 5310 (Seamless Steel Tubes for High Pressure Boilers) |
| Grade | 15CrMoG |
| Type | Cr-Mo Pearlitic Heat-Resistant Alloy Steel |
| Main Applications | High-temperature & high-pressure piping (Boilers, Petrochemical) |
| Key Properties | High creep strength, Good oxidation resistance (up to ~580°C) |
| Delivery Condition | Normalized + Tempered (N+T) |
| Equivalent Grades | ASTM A213 T11, EN 13CrMo4-5 (1.7335) |
For specific projects, it is essential to refer to the complete GB 5310 standard and consult with the pipe manufacturer to ensure all technical requirements, including non-destructive testing (NDT) and hydrostatic testing, are met.
