Question

What should be the maximum desirable thickness of the coatings applied to the mould?

(a) 0.8 mm

(b) 2 mm

(c) 5 mm

(d) 10 mm

I had been asked this question in an interview for job.

I want to ask this question from Permanent Mould Casting topic in section Special Casting Techniques of Casting-Forming-Welding I

Answer 1

Correct answer is (a) 0.8 mm

To explain I would say: The main requirement of a coating is that it should be inert to the casting alloy. The coating can be applied by brushing or spraying. It should be thick enough to fill up any surface imperfections. Generally, the maximum desirable thickness of a coating of refractory material is about 0.8 mm.