What is Stainless Steel?

Stainless steel is a shortened term for stainless and acid-resistant steel. Steel grades that resist weak corrosive media such as air, steam, and water, or possess stainless properties, are referred to as stainless steels; while those that resist chemical corrosive media (such as acids, alkalis, salts, and other chemical erosions) are known as acid-resistant steels. The difference in their chemical compositions leads to varying degrees of corrosion resistance. Ordinary stainless steel generally does not resist chemical media corrosion, whereas acid-resistant steel typically possesses stainless properties.

 

Common Furniture Hardware Made from Stainless Steel

In our daily lives, common sofa hardware such as sofa legs and frames can be made from stainless steel. Additionally, stainless steel is used for home decoration elements like stair railings and elevator decorative panels. These are considered acid-resistant steels and are categorized as high-end steel grades.

 

Materials for General Construction and Industrial Use

General construction materials like steel pipes, mold steel, screws, springs, and the like are typically made from ordinary stainless steel, which can rust. Therefore, their surfaces require treatment. These are classified as non-chemical-resistant steels and are considered ordinary steel grades.

 

Types of Stainless Steel

Stainless steel is commonly categorized by its microstructure into: Martensitic stainless steel (Cr series), Ferritic stainless steel (Cr series), Austenitic stainless steel (Cr-Mn-Ni series / Cr-Ni series), Austenitic-Ferritic (duplex) stainless steel (Cr-Ni series), and Precipitation Hardening stainless steel, among others. Additionally, they can be classified by composition into: Chromium stainless steel, Chromium-Nickel stainless steel, and Chromium-Manganese-Nitrogen stainless steel.

 

Stainless Steel Grades

Forging stainless steels of various standard grades are denoted by a three-digit number. By composition, they can be divided into the Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni (200 series), Heat-resistant Chromium alloy steel (500 series), and Precipitation Hardening series (600 series). The 200 series belongs to the general stainless steel category (with some special high-end steel grades within the 200 series). The 300 and 400 series are considered high-end steel grades. The 500 and 600 series are the top-tier, special steel grades.

 

Common Stainless Steel Types (A Few Usual Types)

200 Series: Chromium-Manganese-Nickel;

201, 202, and other series: Substitute manganese for nickel, with relatively poor corrosion resistance, widely used in China as a low-cost substitute for the 300 series;

300 Series: Chromium-Nickel Austenitic stainless steel;

301: Good ductility, used for formed products. It can also be rapidly hardened through mechanical processing. Good weldability. Better wear resistance and fatigue strength than 304 stainless steel;

302: Corrosion resistance is the same as 304, but with relatively higher carbon content, thus better strength;

303: Added trace amounts of sulfur and phosphorus make it easier to machine than 304;

304: A general-purpose type; also known as 18/8 stainless steel. Used in products such as corrosion-resistant containers, cutlery, furniture, railings, medical equipment. The standard composition is 18% chromium plus 8% nickel. It is a non-magnetic stainless steel whose microstructure cannot be altered by heat treatment. GB grade number is 10Cr18Ni9Ti;

316: The second most widely used steel grade after 304, mainly used in the food industry, watch and jewelry, pharmaceutical industry, and surgical instruments. The addition of molybdenum gives it a special structure against corrosion. It has better anti-corrosion performance against chlorides compared to 304 and is also known as "marine steel." SS316 is commonly used in nuclear fuel recycling devices. 18/10 grade stainless steel usually meets this application level;

 

Performance of These Materials (Commonly Used)

201: Substitutes manganese for nickel, with poor corrosion resistance, not acid and alkali-resistant, prone to rusting.

Commonly used for structural parts, such as reinforcement fixtures, springs, screws, rivets, etc.

301: Good ductility, used for formed products, 301 is slightly harder than 304, making it more difficult for stretching and other processing. Good weldability, better wear resistance and fatigue strength than 304 stainless steel. Corrosion resistance is worse than 304, magnetic, and prone to rusting. Commonly used for structural parts, such as reinforcement fixtures (in the early days of smartphones, the steel plates used for the front shell with in-mold injection were basically made of this grade), springs, screws, rivets, etc.

304: A versatile stainless steel material, also good at high-temperature resistance, generally with a usage temperature limit below 650°C. 304 stainless steel has excellent corrosion resistance and better resistance to intergranular corrosion, non-magnetic. Commonly used for mobile phone casings, exterior parts of electronic products, industrial corrosion-resistant containers, food utensils, furniture hardware, railings, medical equipment, etc.

Rust prevention performance: 304>301>201

 

Stainless Steel Appearance Effects and Processes

1. Surface finishing effects

Can be divided into brushed effects, sandblasting effects, the coarseness of which is determined by the sand belt, generally divided into grades such as 120/150/180/220, etc., in addition to high-luster mirror effects, corrosion matte effects, laser-engraved matte effects, machine-processed CD pattern effects.

 

2. Surface electroplating effects

If using 304 or 316 stainless steel, for a high-luster mirror appearance, electroplating can be omitted, and the original color can achieve the desired effect. If required, electroplating can be done, and the coloring can be colorful, determined by the color number.

 

3. Sofa leg product treatment process

Raw material → stamping → polishing → (brushing or sandblasting or other) → cleaning → electroplating → laser engraving or screen printing characters → packaging completed

 

4. Appearance effect inspection requirements can be customized according to individual requirements.

 

Stainless steel is a very common production material in our furniture hardware - sofa legs. There are many appearance treatment processes for stainless steel sofa legs, and the commonly used stainless steel materials for sofa legs are 301 and 304.