Secondary operations
Secondary operations are the steps between a raw or machined part and the part you install: heat treatment, surface treatment and coating, painting and assembly. QProcess includes them in the same order as casting, forging or machining, so you have one contact and one set of documents for the finished part.
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At a glance
Documents
- Heat treatment records and hardness reports
- Coating thickness reports
- Salt spray test results if specified
Heat treatment
Heat treatment sets the hardness, strength and toughness the drawing requires. The common treatments are:
Normalising (+N)
refines the grain structure of forgings and castings and gives uniform properties before machining.
Quenching and tempering (+QT)
gives high strength and toughness, for example for 42CrMo4 and 34CrNiMo6 shafts and forgings.
Case hardening
(carburising and hardening) gives a hard, wear-resistant surface with a tough core, for example for 16MnCr5 gears and pins.
Induction hardening
hardens selected zones such as bearing seats or gear teeth while the rest of the part stays soft.
Results are documented with a heat treatment record and hardness test results; case depth is reported where specified.
Surface treatment and coating
Hot-dip galvanising
to EN ISO 1461 for steel parts and structures exposed outdoors.
Electroplated zinc
with passivation for small steel parts, fasteners and turned parts.
Electrostatic powder coating
for durable top coats in RAL colours.
KTL (cathodic electrocoating)
for even corrosion protection on all surfaces, often as a primer under a top coat.
Anodising
for aluminium and passivation for stainless steel.
Coating thickness is measured and reported. Corrosion protection requirements, for example a corrosivity category to ISO 12944 or a salt spray test to ISO 9227, are agreed where your specification calls for them.
Painting
Wet painting with primer and top coat is used for large parts, castings and welded assemblies, and where a specific paint system is prescribed. Colour, paint system and masking of machined surfaces are agreed on the drawing or in the order.
Assembly
Parts can be delivered as sub-assemblies: bearings and bushings pressed in, fasteners and seals fitted, machined and cast parts joined. Assembled units are checked against the drawing and the agreed test, and packed for export.
One contact for the finished part
Secondary operations are part of the same order as the casting, forging or CNC machining. We plan the sequence, choose the specialists and check the result, so you do not have to coordinate further suppliers. You receive one finished part with one set of documents.
Documents for secondary operations
Typical documents are heat treatment records and hardness reports, coating thickness reports and, where specified, salt spray test results. More on the quality page.
Drawings are sent to manufacturers only after your company name and logo have been removed. Request a quote or read how we work.
Frequently asked questions
Why order heat treatment and coating together with the part?
Because the steps depend on each other. Heat treatment affects machining allowances and distortion, coating thickness affects fits and threads. When one party coordinates the sequence, responsibility for the finished part stays in one place.
Which heat treatments can you provide?
Normalising, quenching and tempering, case hardening and induction hardening are the most common. The treatment is selected from the material and the required properties on your drawing, and documented with a heat treatment record and hardness results.
What is the difference between powder coating and KTL coating?
Powder coating applies a dry powder electrostatically and cures it in an oven; it gives a thick, durable top coat in many colours. KTL, cathodic electrocoating, deposits paint from a water bath onto all surfaces, including cavities, and is often used as a corrosion-resistant primer under a powder or wet top coat.
Send your drawing. You get a quotation in 3 to 5 working days.
Your drawings are handled confidentially; NDA on request.