Listed manufacturers
What is a steel casting?
Molten steel is poured into a mould, usually of sand, and left to solidify before being cleaned and heat treated. Steel melts at a higher temperature than iron and shrinks more as it cools, so it needs careful design of risers and feeders to avoid defects. After casting, parts are normally heat treated to give the required strength and toughness and then machined and inspected.
Steel Casting or iron casting?
Steel castings are stronger, tougher and can be welded and heat treated, so they suit heavy loads and shock, but they cost more and are harder to cast. Iron castings are easier and cheaper and suit parts with moderate loads.
What to specify when you ask for a quote
- The steel grade and the standard it must meet, with the mechanical properties required.
- Heat treatment: normalising, quenching and tempering or other.
- Casting weight, size and tolerance class, and the machining allowance.
- Testing: chemical, tensile and impact tests, and non-destructive testing of critical areas.
- Pattern ownership and the lead time for new patterns.
- Welding repairs allowed and the procedures and records for them.
Where it is used
Frequently asked questions
When should I use a steel casting instead of a forging?
When the shape is complex and the loads are high, but a forged part would cost too much to machine from solid. Forging is preferred for the highest strength and fatigue resistance in simple shapes.
What is a riser?
A reservoir of molten metal attached to the casting that feeds it as it shrinks, so that voids do not form in the part. Good riser design is central to sound steel castings.
Can steel castings be welded?
Yes. Many grades can be welded for repair or assembly with correct procedures, pre-heat and post-weld heat treatment. Agree repair limits with the foundry.
What tests does a foundry usually perform?
Chemical analysis, tensile and impact tests on test bars, hardness and, for critical parts, ultrasonic, magnetic particle or radiographic inspection.