Dear all experts


If I never specified the heat treatment for carbon steel such as SA 516/515/517, SA 105 and forged flange. What is the condition of the above mentioned CS? Fine grain? Coarse grain? Pearlite? ferrite?


Regards
Ethanhan

The heat treatment condition and grain structure will depend on:
1. the material specification, e.g. SA-516 is a fine grain, and SA-515 is a coarse grain material;
2. the material thickness, e.g. SA-516 must be normalized for all thicknesses above 1,5 inches (40 mm); under this 40 mm you may get either the normalized, or the as-rolled condition; other e.g. SA-105 flanges class 300 and above must be delivered in the normalized condition; SA-105 flanges smaller than class 300 can be delivered normalized or not.

So, I mean, knowing certain material specifications and certain thicknesses you may expect a known heat treatment condition; otherwise it can be anything according to the practice of the mill. So, if you absolutely want to be sure, the heat treatment condition must be specified in the Purchase Order.

Dear Mertens


Thanks you for your above explanation. Your reply is benefit to me. In addition, I would like to know which info, references ,study material can be recommended? Especially how you identify the material grain size, and hence we know the property of the material.




Thanks
Ethanhan

For ASME materials, the grain size is measured per ASTM E-112 standard.
The grain size is quantified by a numbering system. Coarse 1-5 and fine 5-8. The number is derived from the formula N=2exponent (G-1) where G is the number of grains per square inch at a magnification of 100 X.
It must be said that grain size has an important effect on physical properties: for service at ordinary temperatures it is generally considered that fine grained steels give a better combination of strength and toughness, whereas coarse grained steels have better machinability but you must not stick to grain size only because there are many other parameters defining the physical properties of the steel such e.g. tensile strength, elongation, impact test results, hardness, .....

For ASME materials, the grain size is measured per ASTM E-112 standard.
The grain size is quantified by a numbering system. Coarse 1-5 and fine 5-8. The number is derived from the formula N=2exponent (G-1) where G is the number of grains per square inch at a magnification of 100 X.
It must be said that grain size has an important effect on physical properties: for service at ordinary temperatures it is generally considered that fine grained steels give a better combination of strength and toughness, whereas coarse grained steels have better machinability but you must not stick to grain size only because there are many other parameters defining the physical properties of the steel such e.g. tensile strength, elongation, impact test results, hardness, .....

More information can be found in books about metallography, metals technology, metallurgy, relevant Code and standards, .....

If u specified or not it is the depands on your client specifications what they have ask for.
other thing very nicely define by Mertens.

_________________
Niraj