AISI 410 Vs 420

Arrrrroooooogah! Undefined "we" alarm.

He maybe can but you maybe cannot.

Alarmbells are ringing when you say has different strenght, dont you think?

Define what you need and then decide what you are going to use.

They are NOT the same material.

What does the valve material specification allow you to use?

You are obviously trying to save money on these parts, perhaps at the expense of your product reliability, your customer's end use, your customer's reputation and your reputation.

If none of these things are important to you, or if the valves you build from these parts can't be traced back to your business, then you might get away with it.

Don't use it, unless it meets your, and your customer's, specifications and performance requirements!

NO!

I am procuring valves on behalf of cilent. Its an PC contract. The Engineering is already done before and I hav client apprvoed valve datasheets availabe with me. The client is already done with engineering consultant and I am a project piping engineer, so I now dont hav the liberty of consulting the specialists. I did my own research by checking their chemical compositions and mechanical properties. Having done all these I thought 'Let me have a discussion on this to gain some opinions' so I posted this 'We' means we the engineers who engineer projects on behalf of our clients. Data sheet given by consultant (Technip) calls for AISI 410 and a valve vendor has offerrd AISI 420. I can straight away reject telling 'U follow the spec or u r out of business' but thats not what '''WE'''' engineers do I suppose.

"THIS" engineer would ask the customer for a deviation or some type of authorization document.

In lieu of that you can borrow my stamp.

Normally the valve spec provided will state what type should be used. If you want to propose something different from the spec, it should be equal or better for "the client to consider".

Agree with you.

Specs have to be met or exceeded. No penalty in going better other than the cost although sometimes better is cheaper if there are availability issues to contend with.

If you have to complete a compliance certificate with your supply proposal then just say it exceeds the specification (if it really does) at that item or if it doesn't (but the cost saving can be passed on to the client) make a well researched call and say it's fit for purpose under the operating conditions it will be subjected to.

Depends really, doesn't it?

At the very least, you would have to recalculate the thickness of various parts in order to achieve the same strength. Also address hardness, abrasion, and corrosion issues.