Services & Facilities

KTH Holts can heat single items weighing nothing more than a few grams to much larger items weighing tonnes. We can also consistently and uniformly process tens of thousands of components to the highest tolerance and specifications.

The services we are able to offer are due to the extensive amount of facilities we have onsite resulting in offering our customers such an array of services to resolve any challenge or requirement.

Some of our popular services we offer include ;


Distortion can occur for many reasons, machining, heat treatment, damage  once it has occurred we are very well equipped to rectify the problem by offering precision straightening to within a few thousands of an inch or tenths of mm. Uniquely we can offer hot straightening for tough materials and much of our work combines stress relieving and straightening cycles to ensure the long term stability of the component.  We have the facilities for the straightening of case hardened, induction hardened and flame hardened shaft, rolls and other components as well as alloy steel in finish machined or semi machined condition.

Carburising & Hardening

KTH Holts specialise in deep case depth carburising and in minimizing the distortion induced by hardening carburised and through hardening steels. Almost all of our work is carried out vertically to reduce distortion and we frequently hang the components to eliminate sag and bending. Bespoke processes are created to account for alloy, geometry and potential risks as well as customer / end user requirements. As well as the latest in-process controls we use the sampling of test pieces to follow the progress of the depth and quality of the carburization. KTH Holts can provide full mechanical testing, certification and complete traceability on all their work

Stress Relieving

KTH Holts offer thermal stress relieving with tight temperature tolerances and the facility to ramp temperatures up and down at controlled rates.   We design our stress relieving processes to reflect customer specification, material, workpiece geometry and any requirements for bespoke jigging for safety or to prevent the risk of damage as work may be finish machined.

We can stress relieve  a wide variety of materials,  grades, component shapes and sizes ranging up to 5 metres in lengths or up to 1.6 metres in diameter.

We can combine stress relieving with pre and post process straightening, flattening or other processes to return the work to “True”. Contact us for details on our capabilities and capacities.


Holts developed the first “zero” white layer nitriding process and KTH Holts continue to use the same principles to deliver high quality nitriding that requires minimal post process finishing. KTH Holts can Nitride up to 4 tonnes and 2400x1600mm on request.

Vacuum Heat Treatment

Vacuum Heat Treatment is at the heart of KTH Holts’ NADCAP approvals. All the work carries full accreditations and traceability.

We also offer a number of other services ;

  • Ageing

  • Annealing

  • Austempering

  • Carbonitriding

  • Nitriding

  • Case Hardening

  • Flame Hardening

  • Hardening

  • Tempering

  • Hamogenizing

  • Induction Hardening

  • Martempering

  • Nitrocarburizing

  • Sub-Zero Treatment

  • Normalizing

  • Precipitation Hardening

  • Solution Treating

  • Stabilizing

  • Hot Straighten

  • Aqua Blasting/ Vapour Washing

  • Shot Blasting

  • Sub-Critical Annealing

  • Hardness Testing

  • Metallography

  • Failure Investigation & Analysis

+ Our Accreditations