Industries / Steel and metal processing
Large Part Machining for Steel and Metal Processing
The heaviest parts in the industry, and the shortest patience for lead time.
A rolling mill stand carries loads that make most other heavy machining look gentle, and the geometry has to survive them. Chock bores have to stay parallel under rolling force. Housing windows have to stay square while thousands of tonnes pass between them. The machining tolerances look ordinary on paper and are difficult in practice because of the scale and the load.
What really shapes this sector is downtime. A mill that is stopped is losing production at a rate that dwarfs the cost of the part, so schedule beats price on a lot of these jobs. Shops that serve it well are the ones that can say honestly when the machine is free and which step is the constraint.
Parts that come through this route
Not an exhaustive list. It is here so you can tell whether your part behaves like these, which is what decides the machine and the sequence.
- Mill stand housingsVery large castings or fabrications with machined windows, among the biggest parts in industrial machining.
- Chocks and bearing blocksBores that must stay parallel to each other and square to the roll axis.
- Press platens and bolstersWide flat faces with T-slot patterns, classic gantry work.
- Coiler mandrels and drumsLong turned parts with segment slots and internal features.
- Furnace rolls and shaftsLong turning with journal tolerances and often a coating or hardfacing step.
- Shear and crop framesHeavy welded structures with machined guide faces and pin bores.
Where this work usually goes
Machine classes that suit the sector. Full typical envelopes and part weights are on the machine class reference.
Floor type boring mill
Housings and frames beyond any table, with the column driven up to the part.
Gantry mill
Platens, bolsters and large flat faces machined in one clamping.
Vertical turning lathe and heavy lathe
Rolls, mandrels and drums, vertical where the diameter dominates and horizontal where the length does.
Materials
Heavy cast steel for housings, S355 and higher strength plate for fabricated frames, 42CrMo4 for rolls and shafts, bronze liners in chocks, and hardfacing where wear rather than load is the failure mode.
Paperwork this sector expects
- Hardness and heat treatment recordsOn rolls, shafts and any hardened surface, with the location of each reading.
- Non-destructive testingOn heavy castings and on welds in load bearing frames.
- Bore alignment reportsParallelism and centre distance between chock bores, measured and recorded rather than assumed.
What to put in the RFQ
On top of the envelope, finished weight, material and tolerance that every heavy part needs, this sector wants these as well.
- Which mill stand or machine the part fits, and whether it must match an existing one
- Parallelism and centre distance between bores, as a relationship with a tolerance
- The downtime or outage window, and whether a partial delivery helps
- Whether an existing worn part is available to measure
- Any hardfacing, coating or heat treatment, and who supplies it
- Handling constraints at the plant, including crane capacity at the receiving end
Have a part like these?
Send the envelope, the finished weight and the sector. We match it with shops that already work to this paperwork. Reply within 24 business hours.