Stainless Steel material specifications 304 L/304 H/ 309S what are the codes stands for?

Question

What is the meaning of S in 309S ?
What stands for L in 304 L ?
What stands for H in 304 H- on what basis it is divided by 304,309,316 etc.?

Answer 1

These are AISI codes which give the composition of the Steel material. The numbers are called the grade and determine the amount of Nickel, Chromium, Carbon and other ingredients in the steel.

Typically:
S means 0.08%C instead of 0.20%.
L means Low carbon
H means High carbon

But look at the information below.

Answer 2

L = LOW CARBON
H = HIGH CARBON