Name: China GB5310-2017 15CRMOG/ ASTM A335 Gr.P12 Alloy Seamless Steel Tube Pipe Manufacturers Suppliers Factory - Shenzhoutong Steel Pipe
Brand: Shenzhoutong
SKU: 299141827

Products Description

Category	Details
Standard	GB/T 5310 (High-Pressure Boiler Seamless Steel Tubes)
Grade	15CrMoG
Type	Cr-Mo Pearlitic Heat-Resistant Alloy Steel
Main Alloying Elements	Cr (0.80–1.10%), Mo (0.40–0.55%)
Tensile Strength	440–640 MPa
Yield Strength	≥ 295 MPa
Service Temperature	500–550°C (optimal), up to 580°C (short-term)
Maximum Steam Parameter	510°C
Heat Treatment	Normalized + Tempered (900–960°C / 680–730°C)
International Equivalents	ASTM A213 T12, DIN 13CrMo44, JIS STBA 22;ASTM A335 Gr.P12

Specifications and Dimensional Range:

Parameter	Typical Range
Outer Diameter (OD)	16 mm – 630 mm (and larger, up to 765 mm)
Wall Thickness (WT)	2 mm – 120 mm
Length	4,000 mm – 12,000 mm (standard), or random lengths by agreement
OD Tolerance	Typically ±1.0% or as specified per GB/T 5310
WT Tolerance	Typically ±10%

15CrMoG Seamless Steel Pipe: A Complete Technical Overview

1. Material Introduction
15CrMoG is a chromium-molybdenum (Cr-Mo) pearlitic heat-resistant alloy steel designed for high-temperature and high-pressure applications. It falls under the Chinese national standard GB/T 5310 for seamless steel tubes used in high-pressure boilers and other high-temperature pressurized equipment.

Nomenclature Breakdown:

"15" – Carbon content of approximately 0.15% (actually ranges 0.12–0.18%)

"Cr" – Chromium alloying element

"Mo" – Molybdenum alloying element

"G" – Stands for "high-pressure boiler"

This material offers exceptional high-temperature strength, creep resistance, and oxidation resistance, making it widely used in power generation, petrochemicals, and boiler manufacturing industries

2. Chemical Composition (GB/T 5310-2023 Standard)

Element	Content (%)	Core Function
Carbon (C)	0.12 – 0.18	Provides base strength; forms carbides with Cr and Mo to enhance high-temperature hardness
Silicon (Si)	0.17 – 0.37	Aids deoxidation and enhances oxidation resistance
Manganese (Mn)	0.40 – 0.70	Improves hardenability and room-temperature toughness
Chromium (Cr)	0.80 – 1.10	Forms a dense Cr₂O₃ oxide film, providing oxidation resistance up to 600°C; refines grain structure
Molybdenum (Mo)	0.40 – 0.55	Suppresses high-temperature creep; significantly enhances sustained strength at 500–550°C
Phosphorus (P)	≤ 0.025	Strictly controlled to prevent grain boundary embrittlement at high temperatures
Sulfur (S)	≤ 0.015	Minimized to reduce hot cracking risks during forming
Nickel (Ni)	≤ 0.30	Residual element, controlled
Copper (Cu)	≤ 0.20	Residual element, controlled

The synergistic effect of Cr and Mo allows 15CrMoG to maintain stable mechanical properties even at temperatures up to 580°C. The material's microstructure in the as-supplied condition is ferrite + pearlite.

3. Mechanical Properties

3.1 Room-Temperature Mechanical Properties (As-Delivered: Normalized + Tempered)

Property	Requirement	Notes
Tensile Strength (Rm)	440 – 640 MPa	Minimum 440 MPa
Yield Strength (ReL or Rp0.2)	≥ 295 MPa (min)	Significantly higher than ordinary carbon steel
Elongation (A)	≥ 21% (longitudinal) / ≥ 19% (transverse)	Ensures good formability and weldability
Impact Energy (KV2)	≥ 40 J (longitudinal) / ≥ 27 J (transverse)	At room temperature; ensures toughness
Brinell Hardness (HBW)	125 – 195 HBW	Provides good machinability

3.2 High-Temperature Mechanical Properties

One of 15CrMoG's core advantages is its performance at elevated temperatures. The minimum proof strength (Rp0.2) at various temperatures is as follows:

Temperature (°C)	Minimum Proof Strength Rp0.2 (MPa)
200	269
250	256
300	242
350	228
400	216
450	205
500	198

At 500°C, the sustained strength over 10⁵ hours (σ₁₀⁵) reaches ≥ 80 MPa, which is more than double that of 20# steel

3.3 Microstructural Stability and Long-Term Performance

During long-term service in the 500–550°C temperature range, pearlite spheroidization gradually occurs.This is a normal aging process where the lamellar pearlite structure transforms into spheroidized carbides, leading to a gradual reduction in thermal strength and mechanical properties. The degree of pearlite spheroidization is widely used as a criterion for assessing the service reliability of this steel grade.

4.Heat Treatment

15CrMoG seamless pipes are supplied in the normalized and tempered (N+T) condition.

Process	Temperature Range
Normalizing	900°C – 960°C
Tempering	680°C – 730°C

Application

Industry	Specific Applications
Power Generation	High-pressure boiler water wall tubes, superheater tubes, reheater tubes, economizers, headers, and main steam pipes
Petrochemical	Heat exchangers, furnace tubes, and high-temperature pressurized piping
Fertilizer Equipment	High-pressure chemical fertilizer equipment and pipelines

Frequently Asked Questions for Buyers

Q: Is thicker wall thickness always better?
A: No. Excessive wall thickness leads to ineffective weight gain. For example, increasing the wall thickness of a 219×6 mm pipe by 1 mm raises costs by approximately 12%.

Q: Can 15CrMoG be used above 550°C?
A: Not recommended for long-term service. While it can withstand short-term exposure, thermal strength significantly decreases above 550°C. For higher temperatures, consider 12Cr1MoVG or other higher-grade alloys.

Q: What is the typical price range?
A: As a reference, the ex-factory price ranges from approximately RMB 10,500 – 14,500 per metric ton (approximately USD 1,450 – 2,000), depending on specifications and market conditions. Note: Prices are subject to significant market fluctuation.

15CrMoG high-pressure alloy tubes are primarily used for manufacturing high-pressure boilers, heat exchanger tubes, and high and medium-pressure pipelines with steam parameters up to 510℃. Additionally, they are also applied in 700℃ ultra-supercritical power plants and deep-sea oil and gas projects