STAINLESS STEEL PRODUCTS

Stainless steel is a corrosion resistant steel alloy with a minimum of 10% chromium. There are different grades and surface finishes of stainless steel produced to accommodate the environment in which the material will be implemented. Unlike carbon steel, stainless steel does not rust when exposed to air and moisture due to the sufficient amount of chromium present. The chromium creates an invisible passive film of chromium oxide that will not let oxygen attack the surface and prevents rusting of the iron base.

Haohua Industry is a stainless steel distributor of more than 20 grades of Stainless Steel. 

Stainless steels can generally be categorized into 7 categories:

Ferritic Stainless Steels

Chromium is their major alloying element 
Ductility and formability less than austenitic grades 
Magnetic 
Highly corrosion resistant, less durable than austenitic 
Cannot be hardened by heat treatment 
Contain between 10.5%-27% chromium and very little nickel 
Common grades: part of the 400 series like 409, 410S, 430 

Austenitic Stainless Steels

Comprise of 70% of total stainless steel production 
Hardenable by cold working 
Usually non-magnetic 
High hardness and yield strength 
Contain a maximum of 0.015% carbon, minimum of 16% chromium and sufficient nickel and/or manganese 
Superaustenitic stainless steels (AL-6XN and 254 SMO)  have great resistance to chloride pitting and crevice corrosion 
Common grades: 300 series like 304, 316, 320, 321, 347,309 

Martensitic Stainless Steels

Highly machinable 
Very strong and tough 
Can be hardened by heat treatment 
Magnetic 
Contains chromium (12-14%), molybdenum (0.2-1%), nickel, (0 - < 2%), carbon (0.1 - < 1%) 
Common grades: 410, 420, 440 

Duplex Stainless Steels

Often divided into 3 sub classes 
Lean Duplex 
Standard Duplex 
SuperDuplex 
Mixed microstructure of austenite and ferrite about a 50/50 mix 
Higher strength and better stress corrosion cracking resistance than most austenitic alloys 
Greater toughness than ferritic alloys, especially at low temperatures 
Good resistance to localized corrosion, particularly pitting, crevice corrosion and stress corrosion cracking 
Common grades: 2205 and 2507

Precipitation-Hardening Martensitic Stainless Steels       

Designed to be formable in the solution annealed condition 
Can be hardened by heat treatment 
Contain chromium and nickel as major alloying elements 
Corrosion resistance is usually better than that of straight chromium ferritics 
Most common grade is 17-4PH 

Superaustenitic Stainless Steels

Same structure as austenitic alloys 
Enhanced levels of elements like chromium, nickel, molybdenum, copper and nitrogen 
Superior strength and corrosion resistance 
Common Grades: AL-6XN and 254 SMO 

Superferritic

Structure and properties similar to ferritic alloys 
Enhanced levels of chromium and molybdenum 
Increased resistance to high temperatures and corrosive environments like seawater