Why is Stainless Steel Ideal for Deep Drawing and Stamping?
- Lower cycle times per piece than metal spinning and welding operations.
- Monolithic parts can be formed from a single piece of sheet or plate material.
- Rather uniform material thickness can be achieved in stainless steel shapes.
- Can create deep parts while avoiding welds from multi-piece construction.
Cost Saving Tips for Stainless Steel Deep Drawn Parts
- Stainless steel tends to strain and harden when cold forming, so minimal deformation is ideal.
- Designs should minimize the depth to diameter (or the length and width) ratio to avoid the need for stress relief processes.
- Typically limit to 2 reductions before needing stress relieving, ratio of depth to diameter ratio in 304 or 316 to no more than 1:1.33 in most gauges.
- Starting at approximately 14 gauge (0.074 in / 1.75 mm) thick material, tensile formability decreases as metal thickness decreases.
Mechanical Properties and Formability of Deep Drawing Stainless Steel
Good – Lowest cost of high quality deep drawing stainless steel material. The high nickel content allows for good deep draw working. Elong = 60%, Yield 34/30 KSI, Tensile 85/75 KSI
Good – More corrosion resistant than 304 grade due to the addition of molybdenum with the same higher levels of nickel, thus allowing for it to be an excellent deep drawing stainless steel. Elong = 60%, Yield 30 KSI, Tensile 75 KSI
Low – 400 series, generally lower cost stainless steel than 300 series since there is typically very little or no nickel, is not ideal for extremely deep parts since the lack of nickel reduces stainless steels deep draw ability. Elong = 30%, Yield 65 KSI, Tensile 95 KSI
Low – 430 is similar to 410 with little less strength. Like 410, material is readily available and is less expensive than 300 series stainless steel. Elong = 30%, Yield 45 KSI, Tensile 75 KSI
Low – 444 stainless steel is similar in its ability to form compared to 400 series stainless grades. Uncommon to 400 series, this specialty stainless grade has Molybdenum added with Titanium and Niobium added to stabilize the microstructure. This allows the material to be similarly corrosion resistant to 316, without the cost of 316 due to the lack of Nickel. The low Nickel also allows for excellent resistance due to corrosion cracking to chloride induced stress, which is why SS 444 is frequently used for parts in contact with tap water. Elong = 20%, Yield 40 KSI, Tensile 60 KSI