316 And 304 Stainless Steel Welded Tubing

Electropolishing – An electrochemical method of surface finish enhancement in which the metal to be polished is exposed to a     suitable electrolyte, typically an acid solution, while carefully controlled current is passed between the object and a cathode. The object to be polished is the anode, and polishing is accomplished through the  uniform removal of surface metal that goes into solution. Surface finish roughness of less than 0.000,010-inch (10 micro-inch) is attainable.

Hardness – Resistance to  deformation  or  indentation.  Materials  with little resistance are called soft; and those with high resistance are called hard. Finer grained structures are harder than larger grained structures. Measured in steel by scientific instruments as   follows:

Brinell machine for sizes over 1/2" in diameter or thickness. Based on measurement of the diameter of the indentation of a standard size ball under a standard applied  load.

Rockwell machine for sizes under 1/2" in diameter or  thickness. Based on a measurement of the depth of penetration of a standard indentor under a standard applied  load.

Heat – A lot of steel produced by a furnace with one chemical composition. Steel melting is a batch process and each batch is a heat. Also known as a melt of steel. In austenitic stainless steels a heat is typically about 200,000 pounds of material, and will yield approximately   8  coils  of  25,000  pounds  each.  Nickel  base  materials  are  typically melted in heats of  10,000  to  50,000  pounds,  yielding  2  to  5  coils  of 5,000  to  25,000  pounds  each.

Heat Number – An identifying number assigned to the product of one melting: e.g. 721299.

Huey Test – A corrosion test for evaluating intergranular corrosion resistance by boiling in refluxed 65% nitric acid for five consecutive 48- hour periods, each period starting with fresh acid. The weight of metal lost is converted into loss in ipy (inches per year) or ipm (inches per month).  ASTM  A262  Practice C.

Hydrostatic Testing –  A  nondestructive  test  procedure  that  checks for holes, cracks or porosity. Tubing is pressurized internally with water to a high pressure, but does not exceed material yield strength.

Inside Diameter (I.D.) – This refers to the opening in the center of a tube, pipe or coil. Also known as the bore of 316 And 304 Stainless Steel Welded Tubing.