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Q What are the common standards for alloy steel pipes?
A The common standards for alloy steel pipes are primarily developed by organizations like ASTM International (US), ASME (US), and the European Committee for Standardization (EN). Here is a breakdown of the most widely used standards:
High-Temperature Service:
ASTM A335 – Seamless ferritic alloy steel pipe for high-temperature service
ASTM A213 – Seamless alloy steel boiler, superheater, and heat exchanger tubes
ASTM A691 – Electric-fusion-welded alloy steel pipe for high-pressure service
Low-Temperature Service:
ASTM A333 – Seamless and Welded Steel Pipe for Low-Temperature Service
Mechanical Applications:
ASTM A519 – Seamless Carbon and Alloy Steel Mechanical Tubing
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Q What are P91 and P92 grades?
A P91 (9% Cr – 1% Mo – V) and P92 (9% Cr – 1.5% Mo – W – V) are advanced creep-strength-enhanced ferritic (CSEF) steels developed for ultra-supercritical power plants
P91 with higher creep strength than P22 and excellent oxidation resistance, maximum service temperature up to 650°C (1200°F)
P92 with improved creep strength over P91 and enhanced weldability, maximum service temperature up to 650°C (1200°F)
These grades allow for thinner walls compared to P22, reducing weight and improving thermal efficiency in power generation systems.
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Q What are the main applications of alloy steel pipes?
A Alloy steel pipes are widely used in:
Power Generation: Boiler tubes, superheaters, reheaters, main steam lines, feedwater heaters
Oil & Gas: Refinery piping, sour service pipelines, downhole tubing
Petrochemical and Chemical Processing: High-temperature process piping, furnace tubes, heat exchanger bundles, corrosion-resistant systems
Aerospace & Automotive: Hydraulic lines, structural components
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Q Do you offer customized alloy steel pipes?
A Yes, customization is available, including: Special grades and specifications; Custom dimensions; Heat treatment requirements; Anti-corrosion coatings and packaging.
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Q Can alloy steel pipe be used in sour service?
A Yes, certain alloy steel grades are suitable for sour service (environments containing hydrogen sulfide, H₂S). Requirements include:
NACE MR0175 / ISO 15156 – Material requirements for H₂S environments in oil and gas production
Controlled hardness levels (typically ≤ 22 HRC for many grades)
Strict chemical composition control (low sulfur, controlled carbon)
Proper heat treatment (usually quenched and tempered)
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Q What is chrome-moly (Cr-Mo) steel pipe?
A Chrome-moly steel pipe (often abbreviated as Cr-Mo or chromoly) refers to alloy steel containing chromium and molybdenum as the primary alloying elements. The most common grades are covered under ASTM A335 (pipe) and ASTM A213 (tube).
Key characteristics: Chromium provides oxidation and corrosion resistance; Molybdenum adds strength at elevated temperatures and resists creep.
