Steel dished Heads Glossary

Glossary on Steel Dished Ends / Heads

Elongation

The increase in the gage length, during tensile testing, that is measured after fracture of the test, expressed as a percent of original gage length.
 

Fiber Stress

Local stress through a small area on a section where stress is not uniform.
 

Filler Metal

The metal that is used in filling the seam when welding.
 

Flanging Machine

A machine that forms the knuckle radius and straight flange.
 

Half-Pipe

A type of heat transfer surface.
 

Heat Treatment

Heating metal heads to suitable temperatures, holding the part at the temperature for a specific length of time and cooling 
at a rate to obtain desired mechanical properties and microstructure. Heating for the sole purpose of hot forming is excluded from this definition. However, heating to achieve both forming and heat treatment can be simultaneous under some conditions.
 

Impact Test

A test to measure the absorbed energy in breaking a test specimen by a single hammer strike as in Charpy Impact testing.
 

Inside depth of dish

Measurement from the inside center of the head to the tangent line.
 

Jacket heads

Heads that are on the outer shell of a double wall vessel.
 

Jacket head

Heads that are covered with some type of jacketed material such as half-pipe or dimple jacket.

Knuckle Radius (KR)

Also known as corner radius. It is the formed radius of the head which transitions the dish portion to the straight flange. 
This process is done on the flanging machine.
 

Material Test Reports (MTRís)

Certified documents supplied by producing mills that show actual chemical composition and physical properties.
 

Minimum Thickness

The minimum thickness a head can be after forming.
 

Find more steel and metallurgical terms in our General Steel Glossary

 
 

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