Common Types of Stainless Steel For Architectural Hardware Metals
Selecting the right stainless steel concerns many aspects of the functionality of product design. In this article, several common types of stainless steel for the architectural hardware metal industry will be explained on their characteristics and how they differ from each other.
AISI 304 Stainless Steel:
- 304 stainless steel is characterized by its Austenitic crystal structure. It delivers adequate performance on corrosion resistance and structural load capacity in internal and external environments. However, 304 stainless steel is not completely free of corrosion, especially in environments with medium of contact containing chlorides. This increases the chance of pitting and crevice corrosion. Thus, indoor application of 304 stainless architectural hardware is predominantly common, considering both economical and performance factors.
AISI 316 Stainless Steel:
- 316 stainless steel is also a type of austenitic stainless steel. But, it exhibits superior corrosion resistance performance to 304 stainless steel. The superior performance results from a higher Nickel element and the existence of Molybdenum in content. Such properties of 316 stainless steel make application in acidic or more corrosive environment more reliable and thus It has a higher cost than 304 stainless steel.
ASTM Duplex 2205 Stainless Steel
- 2205 Stainless Steel delivers higher corrosion-resistant performance than 304 and 316 stainless steel. Chrome and Molybdenum is higher in content than in 316 stainless steel.It has a hybrid crystal structure of Austenite and Ferrite. Due to its robust and durable properties, application is made possible in harsh conditions like costal areas& extreme cold regions and in environments of inevitable contact with corrosive medium. It is considered as a premium alloy for the architectural hardware metal industry.
Other Stainless Steel Standards
Apart from AISI standards, Stainless steel grades from the EN standard may apply for the manufacturing of architectural hardware metals. Dongying Kelin Machinery Technology’s Foundry is capable of customizing stainless steel alloys and executing production according to different alloy standards. Let’s look at “How similar stainless steels under different standards relate to each other?” from the perspective of chemical composition.
Identical But Not Exactly Equivalent
In table 1 are some comparable stainless steel grades in different designations under EN and AISI standards. The comparison does not indicate exact equivalence between any 2 matching grades under the 2 standards but rather they exhibit similar properties, for instance, in chemical composition.
EN | AISI/ASTM |
1.4301 | 304 |
1.4306 | 304L |
1.4401 | 316 |
1.4404 | 316L |
1.4462 | Duplex 2205 |
Table 1-Comparable Stainless Steel Grades Under EN&AISI Standards
A comparison of alloy chemical composition
Taking AISI 316 and EN 1.4401 for example, table 2 are their chemical compositions. Mo,Ni,Cr are the key elements that make stainless steel resistant to corrosion in these grades and thus a content range is necessarily controlled. C,Si,S,P,N are elements to be controlled within a max limit. Differences exist under the execution of their respective standards. However, The differences do not necessarily imply one alloy grade is superior or inferior to the other.
C | Mn | Si | P | S | Cr | Mo | Ni | N | |
AISI 316 | max.0.08 | max.2.0 | max.0.75 | max.0.045 | max.0.03 | 16-18 | 2-3 | 10-14 | max.0.1 |
EN 1.4401 | max.0.07 | max.2.0 | max.1.0 | max.0.045 | max.0.015 | 16.5-19.5 | 2-2.5 | 8-10.5 | max.0.11 |
Table 2-Chemical Composition of AISI 316 and DIN EN 1.4401
Mn | P | |
AISI 316 | 2.0 | 0.045 |
EN 1.4401 | 2.0 | 0.045 |
Table 3-Elements with same value between the two designations
C | Si | S | Cr | Mo | Ni | N | |
AISI 316 | 0.08 | 0.75 | 0.03 | 16-18 | 2-3 | 10-14 | 0.1 |
EN 1.4401 | 0.07 | 1.0 | 0.015 | 16.5-19.5 | 2-2.5 | 8-10.5 | 0.11 |
Table 4-Elements with different value between the two designations
In some practices, they are considered as being identical and suitable for the same applications in architectural hardware metal industry and in different markets. As an OEM manufacturer, Dongying Kelin Machinery Technologies recognizes the above facts and manufactures any stainless steel grade strictly according to the corresponding standards.
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