An open break on the periphery or flange of a head, formed during heading when the outer surface stretches too far, often starting from a seam in the wire. Inspection standards allow small bursts within width and depth limits as long as they do not reach the head-to-shank fillet, and reject larger ones. Bursts and seams are checked visually, with magnetic particle testing used to find tight ones on critical parts.
Couple of head bursts on the flange, they're inside the allowable width, but log it and tell the header operator.
Also heard as
- burst
- head crack
Related terms
Cold heading
Forming bolt and screw heads from wire at room temperature by striking it in dies at high production rates.
Header
The machine that cold heads fasteners, feeding wire, cutting blanks and striking them in a series of dies.
Upset
To thicken part of a wire or bar by squeezing it along its length, the basic move that forms a fastener head.
Mill cert
Shop name for the material test report tracing steel back to its mill heat, chemistry and test results.