Insert Materials & Finishings

Our  Standard inserts are manufactured from fully certified, aircraft quality, 18/8 austenitic stainless steel in accordance with DTD 734A (equipment specifications AMS 7245, EN 2947, W.NR.1.4301). This material yields a high degree of toughness and hardness and is highly resistant to corrosion. It is suitable for operation in temperatures ranging from -160ºC to +420ºC without detriment to its properties and will withstand surges of up to 500ºC.

Additional materials and or finishes/coatings are available for a variety of conditions as listed:-

ALTERNATIVE MATERIALS

Phosphor Bronze : Non ferrous copper/tin alloy in accordance with BS 2783 PB 102 EH (equivalent specification AMS 7247 DIN 17677). This material possesses a very low coefficient of friction combined with good elastic properties and excellent resistance to corrosion fatigue. It is suitable for operation in temperatures ranging from -200ºC to +300ºC.

Inconel X-750 : Heat resisting precipitation harden able nickel base alloy (equivalent specifications AMS 7246, EN 3018, W.NR 2.4669). This material possesses good creep rupture strength and corrosion resistance  at high temperatures. Its lack of cobalt makes it ideal for use in nuclear reactors.  Inconel X-750 is suitable for operation in temperatures ranging from -200ºC to +550º degrees Celsius.

Nimonic 90 : Heat resisting precipitation harden able nickel base alloy in accordance with BS HR 503 (equivalent specifications W.NR. 2.4632, UNS N07090). This material possesses greater creep rupture strength and corrosion resistance than Inconel X - 750, but however its high cobalt content makes it far more expensive. Nimonic 90 is suitable for operation in temperatures ranging from -100ºC to +650ºC.

Alternative finishes and coatings

Cadmium Plate : Electronically deposited Cadmium in accordance with DTD 904C/Def Stan 03-19 (equivalent specifications QQ-P-416 type II, LN 9368).  Cadmium plating provides an excellent barrier between dissimilar metals dramatically reducing the effects of galvanic corrosion, its high lubricity and excellent corrosion resistance prevents seizure and galling between threaded components. Cadmium is unaffected by alkalis and withstands marine conditions far better than zinc.  However, because of its toxic nature, the use of Cadmium plate is limited to the electrical  and aerospace industries. Cadmium plate is suitable for operation in temperatures ranging from -200ºC to +235ºC.

Zinc Plate : Electrolitically deposited zinc in accordance with BS 3382.  Electro-deposited zinc is the most widely applied electroplated finish in industry.  It provides properties similar to cadmium  at a much lower cost. Zinc is suitable for operation in temperatures ranging from -200ºC to +250ºC.

Silver Plate : Electrolitically deposited silver in accordance with DTD 939 (equivalent specifications QQ-S.365, EN 2786). Silver plating is used to prevent seizure and galling between thread components in high temperature applications and is most commonly applied to aero-engine fasteners. Silver plate is suitable for operation in temperatures ranging from -200ºC to +650ºC.

Vac Cad : Vacuum deposited cadmium plate in accordance with DTD 940/Def Stan. 03-28 pt. 2 (equivalent specification MIL-L-8837). Vac Cad has found a niche in the aerospace industry replacing conventional electronically deposited cadmium on components where the risk of hydrogen embrittlement is un-acceptable. Vac cad is suitable for operation in temperatures ranging from -200ºC to +235ºC.

IVD Aluminum : Ion vacuum deposited pure aluminum coating in accordance with Def Stan. 03/28 Pt 1 (equivalent specification MIL 83488). Originally developed by McDonald Douglas, IVD Aluminum is already widely used in the aerospace industry where it is expected to eventually replace cadmium. Because it is vacuum deposited, the technical limitations associated with conventional electro-plating such as hydrogen embrittlement are eliminated. IVD aluminum provides corrosion resistance superior to cadmium in most applications. Its film thickness is uniform and the process is non toxic. IVD aluminum is suitable for operation in temperatures ranging from -200ºC to +500ºC.

Dry Film Lubricant : Solid film heat cured molybdenum disulphide dry film lubricant coating in accordance with MIL-L-8937 provides a low frictional coefficient coating with excellent load bearing capabilities. Dry film lubricant prevents seizing and galling between threaded components and is particularly effective in screw locking insert applications. Dry film lubricant is suitable for operation in temperatures ranging from -100ºC to +250ºC.

P.T.F.E. : Solid film heat cured P.T.F.E. dry film lubricant coating provides a lower frictional coefficient than molybdenum disulphide and is available in a range of colours. As for molybdenum disulphide, P.T.F.E. dry film lubricant prevents seizing and galling between threaded components and is particularly effective in screw locking inserts. P.T.F.E. coating is suitable for operation in temperatures ranging from -100ºC to + 250ºC.