Various materials are available for sheet metal parts manufacturing. Material selection is done based on required strength, corrosion requirements, assembly process and cost constrains.
In this article, we will discuss various sheet metal materials and their applications.
CRCA (Cold Rolled Close Annealed Steel Sheets)
After hot rolling and pickling, steel is cold rolled to reduce thickness. As a result, it becomes brittle that is not useful. To make it useful, annealing is done in closed atmosphere of nitrogen or other non-oxidizing gases. Annealing process, softens the steel and protect it from oxidation.
CRCA steel is highly prone to rusting. Oil is applied after the annealing to improve short term rust resistance. CRCA steel sheets has superior surface quality, dimensional accuracy and Low Cost.
Commonly used CRCA grades are:
- CR1/390 (Ordinary Quality)
- CR1/440 (Ordinary Quality)
- CR2/D (Drawing Quality)
- CR3/ DD (Deep Drawn Quality)
- CR4 / EDD (Extra Deep Drawn Quality)
- CR5 (Interstital Free)
Galvanized Steel sheet
Galvanized Steel is a steel grade with Zinc coating to improve steel corrosion resistance. GI Steel is available in ordinary (O), Drawing (D), Deep Drawing (DD), Extra Deep Drawing (EDD) Grade steel with various coating thickness.
Galvanized steel is further classified based on zinc plating thickness e.g. 600gsm, 450gsm, 350gsm, 275gsm, 220gsm, 200gsm, 180gsm, 120gsm, 600gsm.
600gsm means 600 gram zinc coating in one square meter of steel area.
Aluzinc Steel Sheets
Aluzinc is a steel grade with Aluminium+Zinc coating on steel surface. AZ coating on steel sheets consist of 55 % aluminium, 43.4 % zinc and 1.6 % silicon. It is applied by hot dipping in molten bath.
AZ Coating micro-structure consists of approx. 80 % aluminium‐rich phase and 20 % zinc‐rich phase with a thin inter-metallic layer. This layer metallurgically bonds the coating to the steel substrate. Aluzinc coating provides additional aluminium barrier coating and zinc‐rich component provides sacrificial protection against corrosion at cut edges.
Aluminium Steel Sheets
Aluminium is second most widely used metal in the world. Following are the advantages of aluminium.
- Low Density / Weight
- High Strength
- Superior Malleability
- Excellent Corrosion Resistance
- Good Thermal and Electrical Conductivity
Commonly used Aluminium sheet metal grades are:
- 5052 – H32 : Good Formability, commonly used sheet grade
- 5052 – H34 : Fair Formability, excellent corrosion resistance & Welding characteristics
- 1050 – H14 : Good Weldability
- 5251- H22 : Applications in marine environments
Stainless Steel Sheets
Stainless steel is a corrosion resistant alloy steel containing more than 10.5% chromium. Good corrosion resistance is due to the naturally occurring chromium-rich oxide film formed on the surface of the steel.
Although extremely thin, this invisible, inert film is tightly adherent to the metal and extremely protective in a wide range of corrosive media. The film is rapidly self repairing in the presence of oxygen and damage by abrasion, cutting or machining is quickly repaired.
Properties Of Stainless Steel
- Good Corrosion Resistance
- Ease of fabrication
- Hygienic Grades are available
- Good Weldability
Commonly used stainless steel sheet metal grades are :
- SS-304 L
- SS-304 H