Stainless steels are a family of iron based alloys that contain a minimum of 10.5% chromium (CR). The presence of chromium creates an invisible surface film that resists oxidation and makes the material passive or corrosion resistant (stainless). There are multiple families of stainless steel which are designed for various applications and uses. Stainless grades can be further modified to meet various processing, corrosion, temperature and strength conditions.

Introduction
Grade 904L stainless steel is a non-stabilized austenitic stainless steel with low carbon content. This high alloy stainless steel is added with copper to improve its resistance to strong reducing acids, such as sulphuric acid. The steel is also resistant to stress corrosion cracking and crevice corrosion. Grade 904L is non-magnetic, and offers excellent formability, toughness and weldability.
Grade 904L contains high amounts of expensive ingredients, such as molybdenum and nickel. Today, most of the applications that employ grade 904L are replaced by low-cost duplex stainless steel 2205.

Corrosion Resistance
Grade 904L stainless steels have excellent resistance to warm seawater and chloride attack. The high resistance of grade 904L against stress corrosion cracking is due to the presence of high amounts of nickel in its composition. Moreover, the addition of copper to these grades develops resistance to sulphuric acid and other reducing agents in both aggressive and mild conditions.
The corrosion resistance of grade 904L is intermediate between super austenitic grades, with 6% molybdenum content, and standard 316L austenitic grades. Grade 904L is less resistant to nitric acid than grades 304L and 310L, which are free of molybdenum. This steel grade needs to be solution treated following cold working, to achieve maximum stress corrosion cracking resistance under critical environments.

904L Melting Point
904L Stainless Steel has a melting range between 1300 - 1390 ºC (2372 - 2534º F)

904L Heat Treatment
904L has austenitic stainless steel chemistry and can be strengthened by solution annealing at 1090 to 1175ºC, followed by rapid water quenching. 904L can be hardened using heat treatment.

904L Machining
Grade 904L stainless steels are high purity steels with low sulfur content. They can be machined using any standard methods. These grades can be readily bent to a small radius under cold conditions. Although subsequent annealing is not required in most cases, it should be carried out when the fabrication is performed under severe stress corrosion cracking conditions.
ASTM A276 UNS N08904 904L stainless steel plate

904L Technical Information

904L Chemical Composition:

* Chemistry conforms to requirement of ASTM A276 UNS N08904 (SS 904L)
 
904L Mechanical Properties:
904L Physical Properties:
904L Density:

Other Common available grade : 

Stainless steel 304/304L Grade : 

Type 304/304L is the modern version of "18-8" stainless steel containing approximately 18% chromium and 8% nickel and is the most commonly specified stainless steel used throughout the world. Type 304/304L is a versatile, general purpose stainless steel with good resistance to atmospheric corrosion, and to many chemicals and food and beverages. These grades can be specified in the annealed condition where they have very good formability. Higher nickel versions can be specified to enhance multi-stage deep drawing characteristics. Higher strength, cold-worked conditions can also be specified for Type 304/304L for spring type applications. Type 304/304L is non-magnetic in the annealed condition but may become slightly magnetic as a result of cold working.
Type 304L can be dual certified as 304 when the composition meets the lower carbon limit of 304L and the slightly higher strength levels of 304. Type 304L should be specified for welded applications as the low carbon version eliminates chromium carbide precipitation and enhances the corrosion resistance in the as-welded condition.

Stainless steel 316/316L Grade : 

Alloy 316/316L is molybdenum-bearing austenitic stainless steel. The higher nickel and molybdenum content in this grade allows it to demonstrate better overall corrosion resistant properties than 304, especially with regard to pitting and crevice corrosion in chloride environments. In addition, Alloy 316/ 316L provides excellent elevated temperature tensile, creep and stress-rupture strengths, as well as outstanding formability and weldability. 316L is the lower carbon version of 316 and is immune from sensitization; therefore, it is very frequently used in heavy gauge welded components.

Stainless steel 1.4571 (316Ti)
Stainless steel types 1.4401 and 1.4404 are also known as grades 316 and 316L respectively. Grade 316 is an austenitic grade second only to 304 in commercial importance.
316 stainless steel contains an addition of molybdenum that gives it improved corrosion resistance. This is particularly apparent for pitting and crevice corrosion in chloride environments.
316L, the low carbon version of 316 stainless steel, is immune to grain boundary carbide precipitation (sensitisation). This makes it suited to use in heavy gauge (over about 6mm) welded components.
For elevated temperature applications the high carbon variant, 316H stainless steel and the stabilised grade 316Ti stainless steel should be employed.
The austenitic structure of 316 stainless steel gives excellent toughness, even at cryogenic temperatures.
Property data given in this document is typical for bar products covered by EN 10088-3:2005. ASTM, EN or other standards may cover products sold. It is reasonable to expect specifications in these standards to be similar but not necessarily identical to those given in this datasheet.

Stainless steel grade 316Ti contains a small amount of titanium. Titanium content is typically only around 0.5%. The titanium atoms stabilise the structure of the 316 at temperatures over 800°C. This prevents carbide precipitation at the grain boundaries and protects the metal from corrosion. The main advantage of 316Ti is that it can be held at higher temperatures for a longer period without sensitisation (precipitation) occurring. 316Ti retains physical and mechanical properties similar to standard grades of 316.

Stainless steel 347 grade:

Alloy 347 is a stabilized, austenitic, chromium steel containing columbium which allows for the elimination of carbide precipitation, and, consequently, intergranualr corrosion. Alloy 347 is stabilized by the additions of chromium and tantalum and offers higher creep and stress rupture properties than alloy 304 and 304L which may also be used for exposures where sensitization and intergranualr corrosion are of concern. The addition of columbium also allows Alloy 347 to have excellent corrosion resistance, even superior to that of alloy 321. 347H is the higher carbon composition form of Alloy 347 and demonstrates improved high temperature and creep properties.

Stainless steel 321/321H grade.

Alloy 321 (UNS S32100) is a titanium stabilized austenitic stainless steel with good general corrosion resistance. It has excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 - 1500°F (427 - 816°C). The alloy resists oxidation to 1500°F (816°C) and has higher creep and stress rupture properties than alloys 304 and 304L. It also possesses good low temperature toughness.

Alloy 321H (UNS S 32109) is the higher carbon (0.04 - 0.10) version of the alloy. It was developed for enhanced creep resistance and for higher strength at temperatures above 1000oF (537°C). In most instances, the carbon content of the plate enables dual certification.

Alloy 321 cannot be hardened by heat treatment, only by cold working. It can be easily welded and processed by standard shop fabrication practices.

Stainless steel 309 309S 310 310S grade:

The 309 stainless steel has a higher corrosion resistance and strength compared to 304 stainless steel. This product is versatile and known for its high heat treatment capabilities.Great ductility, weldability, and high-temperature properties make 310 Stainless Steel the ideal choice for projects that require service at temperatures up to 1150 degrees Celsius. Grade 310 resists oxidation and is also used at temperatures up to 1040 degrees Celsius intermittently. Similar to other austenitic steel grades, toughness down to cryogenic temperatures is another feature of 310.
ASTM A276 UNS N08904 904L stainless steel plate