free-machining

Free-machining brass gives a swarf consisting of small chips which clear from the tool very easily.

Because it is not a free-machining grade, high precision machining techniques have been developed by the specialist manufacturer.

The earlier round-pin plugs were manufactured with their pins turned from round free-machining brass stock.

Commonly available modern brasses have lead in the alloy, and are known as 'free-machining brasses'.

The steel is machinable although not free-machining.

As an example, where significant machining is involved, it is more cost effective to specify brass than the initially cheaper free-machining steel.

Super free-machining steels are alloyed with tellurium, selenium, and bismuth.

Free-machining components, valve stems, marine fittings, lever arms, brackets, and light duty gears.

Standard material for timing pulleys is free-machining aluminium alloy (HE30TF).

Not all alloys are suitable; e.g. the free-machining 303 steel contains sulfur, which tends to outgas.

Examples in this publication show that components can be made more cheaply in materials such as free-machining brass than from other materials of lower first cost.

These apply to any good free-machining brass and include a continuous casting technique including rapid cooling in order to keep the insoluble lead globules finely dispersed.

Bismuth has been evaluated as a replacement for lead in free-machining brasses for plumbing applications, although it does not equal the performance of leaded steels.

General free-machining alloy, for low-pressure valves and fittings, hardware, pump components, and railroad catenary fittings.

Equivalentto ASTM C36000, the standard US free-machining brass.

The cutting speeds used for the improved free-machining brass may be up to double those established at present, that is up to 200 surface metres per minute (650ft/min).

CuSP C111 CW114C Free-machining copper-sulphur is the preferred high-conductivity copper for turning.

The 1960s brought growth in thermoelectric applications for tellurium (as bismuth telluride), as well as its use in free-machining steel, which became the dominant use.

Bismuth is used to make free-machining steels and free-machining aluminium alloys for precision machining properties.

At these sizes the cost saving in manufacture from free-machining brass ensures that the finished cost is less than that of any other material that gives similar precision and reliability.

Atlas stated that, while it can produce pre-hardened free-machining 400-series martensitic stainless steel round bar, it has not supplied material for use in building mould bases for plastic injection mould tooling.

Free-machining materials are available that keep production costs low but even the non-free-machining alloys are generally no more difficult to machine than low alloy steels and infinitely preferable to most stainless steels.

Next in recycling feasibility would be sizeable catalysts with a fair bismuth content, perhaps as bismuth phosphomolybdate, and then bismuth used in galvanizing and as a free-machining metallurgical additive.

Effects of other alloying elements Lead The addition most commonly made to brasses to modify their properties is lead, up to 4% of which may be added to alpha-beta brasses to provide free-machining properties.

To avoid bimetallic corrosion problems, cable glands are normally made of free-machining brass for cable entries into cast iron or steel boxes or alternatively of aluminium for use with aluminium boxes.