Surface treatments

For all cases

Coating

Corrosion protection

Functional or decorative galvanic surface coatings? Zinc coatings? We are the right address!

Functional surface refinement improves the properties of the surfaces of a component in terms of corrosion or wear protection, or improves their electrical conductivity or the reduction of friction forces.

Our range of services includes, for example, the following finishes:

  • Phosphating: Zinc or manganese phosphating to ensure improved adhesion of subsequent coatings or to improve slip properties
  • Galvanising: Chromated or passivated CrVI-free zinc coatings to produce a temperature-resistant, visually attractive, economical corrosion protection
  • Zinc-iron deposition: Black chromated or black passivated CrVI-free zinc coatings to produce a visually attractive, economical corrosion protection with uniform layer thicknesses
  • Zinc-nickel coating: Passivated CrVI-free or lubricated or sealed components with uniform layer thicknesses and maximum corrosion protection
  • Zinc lamella coating: CrVI-free corrosion protection with thinnest layers and highest corrosion and temperature resistance, consisting of a mixture of aluminium base coats, which are combined with zinc top coats in an inorganic matrix, also suitable for high-strength fasteners of property classes 10.9 and 12.9

Further surface treatment options

  • KTL
  • Delta Tone, Delta Seal
  • Phosphatisation
  • Geomet
  • Delta
  • MAGNI

Threadlocks

Under dynamic loads, screw connections tend to come loose automatically. If there is lifting of the frictional locking between the head and support and in the thread, a corresponding coating helps.

If constructive measures to maintain the pre-tension force are no longer sufficient, we recommend that you use the anti-rotation locks for thread locking applied by us as spot or 360° coatings. Our technical consulting is happy to help with the right choice.

The range of services we offer includes the following thread-locking coatings:

  • Adhesive anti-rotation locks: according to DIN 267, Part 27, which prevent the automatic loosening of screw connections through the use of micro-encapsulated adhesives. This is provided by polymerisation during tightening to achieve a cohesive connection between the bolt and the nut thread and counteract loosening using a defined torque between the fasteners of an independent loosening.
  • Clamping securing devices: according to DIN 267, Part 28, prevent partial loosening of screw connections, but avoid a complete loss of the fasteners. For coating, a choice is made for a range of different polyamides which increase the surface pressure or the frictional engagement on the thread sides, thereby achieving a clamping effect.

The following advantages are achieved through the use of thread-locking surface coatings:

  • Avoidance of handling and assembly of additional mechanical safety elements such as nuts or washers, and double storage of these elements
  • Layers applied using reproducible processes, which ensure easier and safer assembly, as well as defined process reliability
  • Thread-locking surface coatings have high resistance to oils, greases and other chemicals
  • The ready-to-use surface coating is dry and non-abrasive, as well as a captive component of the connecting element

Heat treatment

To increase the mechanical resistance through targeted modification and transformation of the material microstructure, we specify the heat treatment according to the requirements of our partners.

A common heat treatment for steel components is hardening after mechanical processing in order to adjust the material properties to the respective field of application. Hardening is understood to mean a heat treatment of the steel in which, by heating to austenitising temperature with subsequent very rapid cooling, the crystal structure of martensite (hardness microstructure) is formed.

The austenitising temperature and cooling rate depend on the quality of the steels. The aim of hardening is a uniform microstructure with mostly dissolved carbon.

As a rule, after hardening, another heat treatment, such as tempering or annealing, follows. We are happy to carry out further heat treatments such as case hardening, blacking, nitriding, carburising, annealing, etc.


Finishing

You can always go one step further!

The term "finishing" (fine machining) refers predominantly to machining processes that are carried out to produce very high-quality workpieces. In this case, the quality can relate both to the surface quality or the roughness depth, as well as on the dimensional accuracy, i.e. the permissible tolerated deviation from the finished dimension.

The goal of finishing almost inevitably results in it being the last production step of a multi-step production. This may be a procedure identical to the previous step under different conditions or a completely different procedure.

We have mastered both mechanical procedures, such as grinding, honing or lapping, as well as processes such as chemical or electrochemical processes, for example etching or electropolishing.


Plastic coatings

For high-performance and heavy-duty corrosion protection.

MAX MOTHES has extensive experience in industrial plastic coating of fasteners and works closely with large companies specialising in plastic coating. This ensures optimal advice and the best solution for every application. Custom developments as well as individual adjustments are possible depending on the requirements. Modern production technology as well as qualified and motivated teams guarantee consistent quality even in large batches.

Plastic coated elements are used in aggressive offshore, oil and gas or petrochemical environments to prevent corrosion and galling of the steel. Depending on the pre-treatment, a service life of up to 4,000 hours can be achieved for these parts in a salt spray test. The range of finishing options extends beyond PTFE to powder coatings such as Epoxy and Rilsan or EFTE and PEEK® coatings.

Plastic-coated fasteners are characterised by the following properties:

  • Anti-adhesive surface
  • Good sliding behaviour
  • Low coefficient of friction
  • Highest temperature resistance
  • Good release properties
  • Excellent wear protection
  • Excellent corrosion protection

Colour

Screws in a special RAL colour? Fasteners in a corporate design? We bring colour to the screws!

We finish the surfaces of fasteners by means of powder coating, cathodic dip coating or with varnish, no matter if a single part, small series or mass production, in many common RAL colours. Custom colours are also possible on request.

Only high-quality powder coatings based on polyester-epoxy resin or KTL coatings are used, which ensures metallic surfaces and cavities are coated with uniform layer thicknesses and very good surface qualities.

The coated parts are characterised by the following properties:

  • good chemical resistance
  • good corrosion protection
  • high surface hardness
  • simple and safe processing

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