Magnesium alloys are used around the world thanks to their light weight and high strength properties. They are the material of choice for the fabrication of various automotive, aerospace, industrial and materials-handling applications.
Magnesium alloys are used around the world in a variety of different applications. Thanks to their light weight and high strength properties, they are the material of choice for the fabrication of various kinds of equipment, including automotive, aerospace, industrial, materials-handling and other. Besides structural applications, magnesium is used as a key component in different industrial processes. Some examples include desulfurization (removal of sulfur or sulfur compounds) and the creation of ductile cast iron.
MAGNESIUM ALLOY PROPERTIES
Magnesium is the lightest structural material used today – 75% lighter stainless steel and 33% lighter than aluminum. It combines excellent mechanical strength and stiffness with low density. This makes it ideal for the production of lightweight, yet durable metal components with a high strength-to-weight ratio.
However, magnesium in its pure form can ignite very quickly so in order to be useful for structural purposes it first needs to be alloyed with other elements that will reduce its flammability. Alloyed magnesium gains additional strength for structural purposes, exhibits great castability and good fatigue resistance.
Common magnesium alloying elements include:
A — Aluminum
E — Rare earth metals
H — Thorium
K — Zirconium
L — Lithium
M — Manganese
Q — Silver
S — Silicon
Z — Zinc
Magnesium alloys offer cost-effective solutions for many different types of products. When compared to some other materials, they offer better part consolidation and weight savings. Another great advantage is that some alloys can be heat treated to additionally improve their properties. Most magnesium alloys remain dimensionally stable to approximately 200 degrees Fahrenheit or, in some cases, 350 degrees Fahrenheit. Some can even withstand brief exposure to temperatures as high as 700 degrees Fahrenheit.
Of all the structural metals, magnesium alloys remain some of the most easily machined. They permit easy shaping and fabrication in most metalworking processes: forging, die casting, permanent mold casting, extrusion and rolling.
benefits of using magnesium alloys
There are several reasons why magnesium alloys can present a better choice over some other lightweight alloys. Firstly, magnesium alloys allow manufacturers to preserve lightweight design features without the loss of rigidity and strength. They offer excellent energy management, as well as impact and dent resistance. In general, all magnesium alloys display advanced damping capacity that promotes quieter equipment operation. Some also possess a low galling tendency that enables them to function well as weight-bearing surfaces that won't wear away easily due to friction.
ADVANTAGES OF USING FORGED MAGNESIUM ALLOYS
Forged and heat-treated magnesium alloys exhibit some mechanical properties that are comparable to certain grades of steel. These include:
- superior strength-to-weight ratio;
- porosity-free forging that permits easy heat treatment for the improvement of mechanical characteristics;
- the ability to accept a range of surface finishes;
- lower production costs (forging is generally affordable);
- higher production rates.
alloys specifically designed for forging
Bunty LLC uses magnesium alloys that are specifically designed for forging. Some of these products include:
This medium strength magnesium alloy consists of 3% aluminum and 1% zinc. It offers good corrosion resistance, a high strength-to-weight ratio, and a very high rating for machining. This alloy welds easily, making it useful for a variety of commercial and aerospace applications.
The medium strength general purpose AZ61A magnesium alloy uses 6% aluminum and 1% zinc, considerably more aluminum than AZ31B. With a higher tensile strength and superior corrosion resistance than AZ31B, it permits gas arc welding. This material proves appropriate for making both hollow and solid shapes and it will accept a variety of finishings. Manufacturers use this alloy widely to produce bearing caps and housings, fittings, rocker arm supports, screws and other machine components.
The strongest commercial member of the AZ alloy class, AZ80A provides good strength at temperatures up to 250°F. It supplies good corrosion resistance, too. This alloy makes an excellent choice for manufacturing processes requiring machining or pressure tightness.
This magnesium forging alloy provides high strength and good corrosion resistance. It requires a coating for all applications. Manufacturers have used this product for many years in forged magnesium automotive wheels. It also frequently appears in military uses, and in aircrafts and rotors.
These specialized magnesium alloys sustain high heat and radiation. They possess relatively low strength, however.
The HM21A class of Magnesium alloys usually appears in rolled products. However, HM21A also works well as a forging alloy and tolerates temperatures up to 700 degrees Fahrenheit.
UNDERSTANDING MAGNESIUM ALLOY DESIGNATION SYSTEM
Most manufacturers use a specialized system to designate magnesium alloys. The initial letters of the designation refer to the two alloying elements that are present in the alloy in the greatest amount. Letters are then followed by numbers that express the percentages of the main alloying elements, rounded to whole numbers.
Alloying elements always appear in the order of decreasing percentages, and whenever two elements occur in equal amounts, alphabetical listings control. For example, magnesium alloy AZ61A contains 6% aluminum (A = aluminum) and 1% zinc (Z = zinc).
The final portion of every designation contains serial letters indicating the presence of minor alloying constituents or impurities, and, sometimes, a hyphenated code designating the specific heat treatment process employed. Some examples of common process codes include:
F – Fabricated;
O – Annealed;
H – Strain hardened by cold working;
H1 –Strain hardened only;
T – Heat treated;
W – Solution treated only.