Coolant Incapability

"coolant which is to be mixed with water for cooling suh11 mtl"

And just what is a "suh 11 mtl?"

All coolants for automotive and similar engines require oxidation and corrosion inhibitors to prevent damage to the cooling system.

Yes, you still use water that, in contact with succeptible to oxidation materials, will cause corrosion. And it's not because it has impurities.

Your coolant should have corrosion inhibiter. Some special additives are required in processes that use dissimilar materials in the pipes, causing galvanic corrosion. Take a look at this...

And what the hell is suh11 mtl?

A quick 'Google' tells me that SUH 11 is a heat resisting chrome steel. The presence of water & air, even if the air is dissolved in the water, will cause corrosion. Is your cooling requirement for when this material is being machined? If it is, I would of thought that a standard oil emulsion coolant would solve your problem. If not, then anti-corrosion additives as advised previously are your answer.

Do you use ethylene or propylene glycol in these systems? When exposed to high temperature these glycols will break down into organic acids. You additive package must stabilize against this.

There will be corrosion if there are different metal in the cooling system and the coolant is conductive.