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Processes

Seven processes, one record for each.

Case hardening, through hardening and the treatments around them, in sealed quench furnaces with oil quench and logged tempering. Pick a code to see its typical cycle.

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Every code on the plant wall.

Use the same code when you ask us for a quote.

  1. CHT

    Carburising, hardening and tempering

    A hard, carbon-rich case over a tough core, for gears, shafts and pins that take contact load.

    900 °C · CP 0.98 %SQF → TFC

    Details on carburising
  2. CN

    Carbonitriding

    Carbon and nitrogen diffused together for a shallower, wear-resistant case at a lower temperature.

    C + N atmosphereSQF → TFC

    Details on carbonitriding
  3. THT

    Through hardening and tempering

    Hardened through the section, then tempered back to the hardness the drawing asks for.

    Oil quenchSQF → TFC

    Details on through hardening
  4. TMP

    Tempering

    Relieves quench stress and sets final hardness.

    150–190 °C typicalTFC-1, 2, 3

    Details on tempering
  5. SR

    Stress relieving

    A soak below the transformation range to relax machining and welding stresses without changing hardness.

    Sub-critical soakSet per grade

    Details on stress relieving
  6. CCA

    Annealing

    Softening and structure control ahead of machining.

    Cycle per gradeSet against the drawing

    Details on annealing
  7. NPD

    Development trials

    Trial charges for new parts: we set the cycle, section the samples and report before you release production.

    Trial chargeSectioned + reported

    Details on development trials

Shared route

Every hardened lot takes the same nine steps.

Only operation 50 changes between CHT, CN and THT. The numbers match our process inspection record.

  1. 10Visual inspectionParts counted and checked against the delivery challan on receipt.Inward
  2. 20JiggingLoaded to the jigging work instruction for this part.Fixture trays
  3. 30Pre-washMachining oil removed before the parts enter the furnace.Washer · 45 ± 5 °C
  4. 40Pre-heatCharge brought up evenly before the process temperature.SQF
  5. 50Harden in the sealed quench furnaceCarburise, carbonitride or austenitise, then quench in agitated oil without leaving the atmosphere.SQF-1, 2, 3
  6. 60Post-washQuench oil removed.Washer · 50 ± 10 °C
  7. 70Temper, air coolStarted within 4 h of the quench, soak recorded.TFC-1, 2, 3
  8. 80InspectionHardness, case depth and microstructure on samples per the sampling plan.Lab
  9. 90DespatchReleased only after the 12 checks pass and the report is signed.Test report

50 operation specific to each process

Next step

Not sure which process your part needs?

We will propose the process and cycle, or a trial charge first.

Request a quote Development trials