Casting defects · pouring

Misrun casting defect

A misrun is a casting that did not fill - thin sections missing, edges rounded where metal froze before it arrived. It is the same story as a cold shut, one step further.

By Versatile Equipments Pvt Ltd · equipment manufacturer & calibration provider · updated 2026-07-15

What it is

A misrun is an incompletely filled casting: thin sections, edges or far features are missing, with smooth rounded ends where the metal ran out of heat and stopped. The metal lost fluidity before it filled the cavity.

Misrun or short pour?

If the ladle simply ran empty, the casting is poured short - the top is missing and the metal level is flat. A misrun fails in thin or distant features while heavier sections filled, because fluidity, not volume, ran out. A cold shut is the milder version where fronts met but did not fuse.

Root causes

Low pouring temperature and low metal fluidity.
Slow or interrupted pouring.
Very thin sections and long, restrictive flow paths.
Back pressure from poor mould and core venting resisting the fill.

Prevention checklist

Raise and control pouring temperature for the thinnest section that must fill.
Improve fluidity and gate for a fast, clean fill of thin features.
Vent the mould and cores so trapped air does not fight the metal.
Shorten flow paths to thin areas; add ingates where filling is marginal.
Log misruns by part and feature; a feature that repeatedly fails names a fluidity or venting fix.

Frequently asked questions

What causes a misrun in casting?

The metal loses fluidity before it fills the cavity - from low pouring temperature, slow or interrupted pouring, very thin sections and long flow paths, or back pressure from poor venting. Thin and distant features are missing while heavier sections filled.

What is the difference between a misrun and a cold shut?

A misrun is metal that did not fill part of the cavity; a cold shut is metal that filled but two fronts met without fusing. They share causes - cold, slow metal - so a fix that raises temperature and speeds filling usually helps both.

Log defects on the floor, free

CaRe 101 is a free shop-floor app from Versatile: your team photographs the casting, marks the defect and taps its name - no typing, works offline. The rejection register builds itself, so you can see which defects hit which parts and act on the pattern.

Open CaRe 101 - free See how it works