مقدمهٔ تفصیلی بر انواع و اقسام فولاد ضد زنگ

Stainless steel is an iron-based alloy containing at least 10.5% chromium. Chromium forms a protective chromium oxide layer on the surface, preventing rust from penetrating the iron.Stainless steel can be classified into duplex structure classes and single heat-treatment classes, which fall under the same general category for most types. The numbering system divides stainless steel into five categories: martensitic, austenitic, ferritic, duplex, and precipitation-hardening.In this article, we will examine the different types of stainless steel.

فولاد ضدزنگ مارتنزیتی

Martensitic stainless steels are a class of stainless steel whose properties can be adjusted through heat treatment (quenching, tempering). These steels primarily consist of iron and carbon (up to ~2 wt.%), with chromium content ranging from 10.5% to 18% and carbon content not exceeding 1.2%.

For Grade 403, no additional parameters are specified—it is a basic martensitic stainless steel. Other martensitic steels (e.g., 403, 410, and the 400 series) are considered hardenable.

Applications:

• Jet engines

• Gas turbines

• Valve components

• Cutlery

• Petrochemical equipment

Key Mechanical Properties:

• Moderate work-hardening rate

• Heat-treatable

• Good ductility and toughness

• High tensile strength

• Good creep and fatigue resistance

• Magnetic

فولاد ضد زنگ آستنیتی

The most common type of chromium alloy, austenitic stainless steel has a face-centered cubic (FCC) crystal structure, similar to high-temperature iron. The primary alloying elements are chromium-nickel (Cr-Ni) and chromium-manganese-nitrogen (Cr-Mn-N), categorized by application.

Composition:

• 16–26% chromium

• ≤0.15% carbon

• Up to 35% nickel (for cold-working and strain hardening)

• Manganese (≤1/7 Mn per standards)

• Silicon (0.75–3% for high-temperature strengthening)

• Additional elements (e.g., sulfur, nitrogen, molybdenum, selenium, copper)

Magnetic austenitic grades: 201, 202, 205.
Non-magnetic grades: 304 (industrial standard, ≥8% nickel).

Applications:

• Appliances

• Screws and undercut components

• Chemical mixing tanks

• Pressure vessels

Mechanical Properties:

• Excellent work-hardening rate

• Superior ductility and toughness

• High tensile strength

• Good creep and fatigue resistance

• Scale resistance (up to 650°C)

• Moderate heat resistance (≤650°C)

• Excellent weldability

فریتیک فولاد ضد زنگ

Ferritic stainless steel has a body-centered cubic (BCC) structure, with 10.5–30% chromium and ≤0.2% carbon. Common alloying elements include molybdenum, silicon, aluminum, titanium, and niobium.

Basic grade: 430.
Enhanced grades: 434 (standard), 409 (titanium-stabilized), 439, 444 (super ferritic).

•  تجهیزات فرآوری مواد غذایی
• Chloride solution pipelines
• Heat exchangers (≤250°C)

• Automotive interiors

Mechanical Properties:

• Low work-hardening rate

• Moderate ductility and toughness

• High tensile strength

• Good creep/fatigue resistance at low temperatures

• Moderate corrosion resistance

• Good heat resistance

• Poor weldability

• Magnetic

Duplex Stainless Steel

Duplex stainless steel combines ferritic (BCC) and austenitic (FCC) structures. It offers corrosion resistance comparable to Grade 316 austenitic steel but with higher tensile strength and improved stress-corrosion cracking resistance.

Composition:

• 22–26% chromium

• 4–7% nickel

• ≤0.6% copper

• 0.15–0.25% nitrogen

Categories:

• Lean duplex (2304)

• Standard duplex (2205)

• Super duplex (2507)

• Hyper duplex (Zeron 100)

Applications:

• Oil & gas

• Chloride water treatment

• Seawater desalination

Mechanical Properties:

• High work-hardening rate

• Non-heat-treatable

• Good ductility/toughness

• مقاومت عالی در برابر خوردگی

• Moderate weldability

Other Notable Grades

201 Stainless Steel

• ترکیب: Cr-Mn-N alloy (16–18% Cr, 3.5–5.5% Ni).

• کاربردها: Food handling, architectural components.

• Properties: Non-magnetic (annealed), cold-work hardenable.

2507 (Super Duplex)

• ترکیب: 25% Cr, 7% Ni, 4% Mo.

• کاربردها: Desalination plants, chemical processing.

304/304L/304H

• 304: General-purpose (18% Cr, 8% Ni).

• ۳۰۴ال: Low-carbon variant for welding.

• ۳۰۴H: High-temperature stability.

316/316L

• Molybdenum-enhanced for corrosion resistance.

• کاربردها: Marine, chemical processing.

430 (Ferritic)

• Cost-effective, moderate corrosion resistance.

• کاربردها: Automotive exhausts, heat exchangers.

خلاصه

This article detailed stainless steel types, grades, and properties. For further inquiries, contact DAXUN for manufacturing services or a free quote.

سلب مسئولیت: The content is for informational purposes only. DAXUN does not guarantee accuracy. Specifications depend on supplier compliance. Refer to our Terms & Conditions for details.