Stainless Steel 321 / 321H Seamless Pipe

The addition of titanium while boosting strength is a detriment to the machinability of type 321. The metal can only be welded using certain specific welding techniques. If we get beyond this limitation the type 321 alloy has excellent formability as this metal does not need to be annealed after welding. This grade can work in extreme temperatures even down to cryogenic levels. It is often chosen over 304 when the project requires higher creep and rupture resistance. However both types can be susceptible to cracking due to stress corrosion.

Stainless Steel grade 321H is a higher carbon version of the 321. The higher carbon levels promote resistance to high temperature environments. As a result, 321H is preferred where 321 can’t handle the temperatures, especially in environments exceeding 538°C. While its machinability is near identical to 321 it cannot be hardened via heat treatment.

Apart from that the addition of niobium elevates intergranular corrosion resistance further. 321H has some resistance against acid corrosion in various environments. While the resistance is better at low temperatures it can still withstand a 10% acid solution at higher temperatures. The only exception being chlorine and sulfuric solutions against which it performs poorly regardless of temperature. Since both of them have near similar chemical makeup and characteristics it is possible to have 321 and 321H dual certified.

We provide the best competitive prices to our clients backed by quality service.