Primer on Strand Annealing Furnaces

Annealing Furnace, Strand Anealer

In the late 1940’s continuous strand or strip annealing lines came into use in brass producing mills. The modern strand annealing tube furnace has for decades played the dominant role in annealing of wires, ropes and tubes made of stainless steel and nickel alloys. But what is the annealing process and how do CM furnaces specifically facilitate the strand annealing process in a continuous production environment?

Primer on the Process of an Annealing Furnace

An annealing furnace is typically a type of continuous furnace used to heat material at very high temperatures in such a way as to change its hardness and strength. Annealing is often associated with the production of steel and other metals. The process of annealing can help relieve internal stresses or non-uniformities in the material that may lead to early failure in the field. The annealing process (using an annealing furnace) is also commonly used with other metals, glass, and even ceramics to make them less brittle and more durable and workable.

Steel is annealed to reduce the hardness, improve machinability, facilitate cold-working, or to produce a particular microstructure within the steel. This basically involves a heating and cooling cycle that softens the material so that it may be bent or cut easily. For metals, an annealing furnace must be capable of heating the material to a specific temperature, known as the re-crystallization temperature. This produces changes in the atomic structure and causes the metal to soften. While annealing temperatures vary depending on the material and application, a typical temperature for annealing steel is around 1,292°F (700°C). An annealing furnace is designed for very uniform heating, followed by a gradual cooling process To prevent oxidation of the material, the heating chamber is airtight, with a slightly positive pressure. The atmosphere within the chamber typically consists of a combination of nitrogen and hydrogen.

What is a Continuous Strand Annealer?

In the late 1940’s continuous strand or strip annealing lines came into use in brass producing mills.  After many decades of development the modern day horizontal tube based strand annealing furnace was developed.  While many types of furnaces can be used for generalized annealing processes, the CM 200 Strand Annealer is specifically designed to facilitate the manufacture of high quality rods, wires, strands, and tubes made from various kinds of metals. These furnaces are ideally suited for copper, copper alloy, nickel, nickel chrome, titanium, stainless steel and other refractory metals.

The CM 200 is a cost effective solution to a wide range of production strand annealing processes. Three temperature ranges are offered to cover a wide variety of applications. These include the LTSA series to 1000°C (1850°F) utilizing ceramic plate heaters with Kanthal A1 wire; the SA series to 1200°C (2200°F) utilizing silicon carbide heating elements; and the HTSA series to 1750°C (3200°F) utilizing a molybdenum wound muffle. All designs feature top and bottom heating of the process tubes.

Call CM Furnaces for more information on Strand Annealing Furnace solutions for your manufacturing process.