What is Stainless Steel?

Stainless steel is a group of corrosion resistant steels containing a minimum of 12% of chromium. Nickel, Molybdenum, Titanium and other elements may be present in varying quantities.

The composition of these elements govern their properties and behavior of the various types of steel and therefore selection of the appropriate grade of stainless steel is the primary criterion for its success to as given application.

  • Stainless steel is one of the world’s most recycled materials.
  • Stainless steel is definitely a part of the solution.
  • Stainless steel helps in saving planet earth.

Type of stainless steel

Stainless steel ingot we manufacture include three different types

  • Ferritic stainless steel: The ferritic steels are magnetic and have a low carbon content & contain chromium as the main element, typically at the 12% & 17% levels.
  • Martensitic stainless steel: The martensitic steels are magnetic containing typically 12% chromium and a moderate carbon content; they are hard enable by quenching and tempering like plain carbon steels and find their main application in cutlery manufacture, aerospace and general engineering.
  • Austenitic stainless steel: The austenitic steels are nonmagnetic and in addition to chromium, typically at the 18% level, they contain nickel which increases their corrosion resistance and are the most widely used group of stainless steel.


Austenitic stainless steels

301, 302, 303, 304H, 304L, 304L, 304LN, 305, 310, 314, 316, 316L, 316LN, 316 Ti, 317L, 321, 321H, 347, 347H, 201, 202, 204 Cu

Ferritic and Martensitic stainless steels

409, 410, 416, 420, 430, 431, 434, 446, X46CR13, F-1, F-5, F-9, F-11, F-22, F-91

Duplex Steels

F-51/2205, 2304, 2507

Utensil grade steels

Lx-1, LX-4, LX-5, LX-6, LX-7

Nickel chromium molybdenum steels

EN-36C, EN-24, EN-352, EN-353, EN-354, EN-355, SAE-8617, 8620, 8622, 8625, 8627, 4320, 4340

Chromium Molybdenum steels

EN-19, 4120, 4130, 4140, 4145, 25CrMo4, SCM415, 420H, 16Mp3

Chromium molybdenum vanadium & chromium vanadium steels

B-16, EN-47, 50CrV4

Free cutting steels

SAE-1117, 1140, 1141, EN-8DM, 15AM

Carbon Manganese steels

EN-14, EN-15, 37C15, SAE-1541, SA-105, ST52-3

Chromium steels

16MnCr5, 20MnCr5, EN-18, EN-18D, 34Cr4, 41Cr4

The non rust of the stainless steel means it can have chemical stability around the corrosion mediums of air, water, acid, alkali, salt or others. But it does not means the stainless steel does not rust completely. Whether the stainless steel will rust or not is influenced by the molecular structures, the processing technical, the operating environment and so on. TO prevent the stainless steel from rusting extremely, please pay attention to the following factors.

  • The die and casting parts should be carried out the solution treatment according to requirements.
  • Choosing the reasonable stainless steel mark according to the operating environment.
  • Selecting the reasonable surface treatment.
  • Taking protection measures of hardware products into action on site.
  • The application of the hardware should avoid dust deposit and hydrous.
  • Cleaning the hardware should avoid dust deposit and hydrous.
  • Cleaning the hardware regularly to avoid time smudge.

Solution to the stainless steel rusting

A)Stainless steel rusting

Stainless steel have certain chemical stability doesn’t mean you can stop routine maintenance. Its not a good idea to take measures to clean stainless steel after it rust severely. Stainless steel contains chromium which made it not easy to rust and corrosion. Chromium combines with oxygen into dense oxidized film in the air which can prevent stainless steel from oxidation and corrosion. SO the stainless steel products will begin to rust where the oxide firm damaged by some reason and the chromium cant combine with oxygen. The only thing we need to do is guarantee chromium can combine with oxygen cause once the oxide firm produced the stainless steel is not easy rust. Stainless steel rusting for many reasons, largely because of iron floating or harmful gas components in the air and sea breeze contained salt. These things accumulate as attachments, combined with moisture will destroy the oxide firm and its regeneration. The stainless steel products begin to rust. Simple clean can remove the rust in the initial state of this process. The stainless steel products can be look like a new one as long as the removal of work done, even after long time rust. Stainless steel rusting is only the surface of the products but not the material itself. As long as we take regular maintenance, the original appearance of stainless steel products can be kept forever.

B)Reasons of rust and combination
  • Contamination caused by sediment, dust and iron because of road construction, project construction and vehicles.
  • Contamination caused by sulfurous acid gas in exhaust air by card.
  • Contamination caused by harmful components in air
  • Contamination caused by corrosive gas in hot are
  • Contamination caused by the remain cleaning liquid.
  • Contamination caused by the hand or fingerprint
  • Contamination caused by the surface protective film.
C)Maintenance methods
  1. Rust caused by adhered metals
    Less severe rust caused by iron and other incidental rust can be removed by sponge or soft cloth with neutral detergent or soapy water. Then clean with water. It’s easy for this kind of rust, but if treat no timely, there will be hydrogen iron oxide, iron oxide, ferric sulfate and other mixtures on the surface. Cleaning liquid or dilutions of nitric acid 15% can remove the rust, and then brush the ground with sandpaper or stainless steel brush. Clean with the water at the end of the treatment.
  2. Contamination caused by harmful components in air.
    In the are with a lot of workshops and heavy traffic, the harmful ingredients in the exhaust gas coming of the car, heating and air-exhaust or factory waste gas, will leads pollution in the surface of S.S products, sometime even rust. Neutral detergent or soapy water can clean the minor contamination. If it cannot work, then clean with cleaning liquid or dilutions of nitric acid 15% remove rust. Brush the ground with sand paper for severe contamination. Clean the surface with water after treatment. In this area, 2 or 3 treatment is necessary.
  3. Contamination caused by attached salt
    In coastal areas, red rust always happened within short period, and the S.S products rust quickly than other area. Treament as above. S.S 316 is a wise choice for outdoor usage in coastal because of its strong corrosion resistance. Please take 3-4 times cleaning for S.S 304 pillar installed in outdoor in coastal are.
  4. Contamination caused by attached cleaning liquid
    if Neutral detergent cannot clean up, then use cleaning liquid.
  5. Contamination caused by hand or fingerprint
    If neutral detergent cleaning doeant work, then wipe sponge, cloth stained with organic solvents, (Alcohol, benezene, acetone, etc.) if still doesn’t work, use steel cleaning liquid. Take water cleaning after treatment.
  6. Contamination caused by surface protective film.
    Wipe with sponge, cloth stained with neutral detergent or alcohol, take water cleaning after that.
A) Maintenance precaution
  1. Please take suitable measure to clean S.S products
  2. Please make a partial wipe test to confirm the cleaning effect before using the cleaning liquid for the rust. Then do a comprehensive clean. Partial clean will affect the product appearance, sp clean the round of the rust too.
  3. Clean the surface with water after using cleaning liquid otherwise remains liquid will cause rust.
    Cleaning liquid may cause rough or spotted to the skin, so rubber gloves is necessary.
  4. Please follow the direction of the surface line when use cloth, nylon sponge, brush hook, and brush clean S.S product surface. Circular clean will damage the gloss of the appearance and cannot remove impurities totally. Don’t use steel clean appliances or sandpaper, because it will damage the surface of stainless and the attached iron may cause rust.

Generally, Austenic stainless steel is non-magnetic or weak magnetic, but cold work may lead to magnetic. (Quoted from GB/T 20878)

Note : Its unscientific to confirm the austenitic stainless steel by test magnetic.