Radiography Testing for Valves

You may add your suggested paragraph in the specification with condition "where applicable" because on every part of valve or large size valve body, gamma radiography would not work due to body size and metal thickness exceeding 2 inches. Radiography with X-Ray, you need to have large size film cassette to shoot large size valve body for "double-wall-single-image" radiography. You would have no problem with small size valve. Real-Time Radiography might do the job for all. You may use combination of NDT to find flow but Radiography would not find bad metallurgy but bad workmanship. With nondestructive testing you could only find "flows" developed during forging or present in weld joint of flange . Radiography would not warrant against corrosion or HAC (hydrogen assistance cracking). Ask your manufacturer to find better metallurgy with combination of nickel, chromium. and molybdenum for corrosion resistance during service of valve. A.W. Siddiqui

You have nither mentioned the valve type nor the valve body construction, cast or fabricated.

Radiography test is to detect either material flaw or weld joint flaw. Material flaw case is at much earlier stage before start of maching activities. In weld joints also, it is morely useful for butt welds. So you can specify accordingly alongwith other NDT,s to suppliment.

Percentage shall be 100% for weld joints. This test is not recommended for all valves. Only for critical sevices it may be required.

Thanks Abdul and Pritam,

My intention is to be in a safe zone,

About the valve type,

It is included in my question that which types of valve and what percentage?

I believe that forging valves are better than casting so is it o.k. to consider radiography only for casting valve?(or Casting valve and some parts of forging valves? If yes which part do you recommend?)

I just wanted your advice.

Since Sour services and HIC environment are critical I decided to consider Radiography.

What do you mean by weld joint? Do you mean butt weld joints?

I am looking for NDT test for body, bonnet, trim, seat (if it is metal seated valve) and so on,

What do you think?

Thanks,