LEGORPEDIA

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ALLOYS: PRODUCTION PROCESSES

Alloys for casting

Compositions characterized by an improved performance on:
• metal flowability in liquid phase
• increase of filling on complex shapes,
• optimization of scraps reusage without problems,
• minimization of solidification shrinkage.

Legor Group alloys for casting allow you to get the most from each type of casting system (traditional, in closed systems, with or without stones). Once correctly chosen the code depending on the type of machine and product to be obtained, simply follow the values given in the data sheets for best results.

Traditional casting systems

Insufficient bath protection against metal oxidation and lacking control of temperature in the pouring phase.

Alloys characterized by:

• effective level of deoxidation
• good flow to ensure filling
• good control of the solidification structure even in the case of excessive overheating

Casting in closed systems

Excellent control of temperature and of atmosphere in the melting chamber.

Alloys characterized by:

high level of surface compactness and lower need for deoxidizers, with immediate effects on mechanical strength and on a higher shininess of the finished piece.

Stone-in-place casting

Simplicity and speed of the setting of stones in a soft and elastic material like wax, enabling to increase design complexity.

Alloys characterized by:

Low or very low melting temperatures, exceptional fluidity, excellent degree of deoxidation to maintain the shininess and colour of the stones.

All-purpose alloys

The so-called all-purpose alloys are a good solution for those who have the need to use an alloy in both types of process, or do not want to multiply the number of alloys useful in a single colour and carat. Considering that these are alloys with low levels of deoxidizers, it is preferable to use all-purpose alloys in case productions are for the most part of mechanical processing and only in part of casting.

Alloys for mechanical working

The variety of types of processes dedicated to the production of jewellery is made possible by the great intrinsic ductility and malleability of gold and silver alloys. It is up to the Research to provide solutions that push this characteristic to the limit, increasing the maximum levels of deformation and toughness, together with shininess, corrosion resistance, weldability.

Production of sheet: requires alloys that ensure high lustre and compact surface, combined with an excellent colour. The range goes from very soft alloys for the production of stamped items, to others with a certain stiffness for blanking. For the production of extremely thin sheets, age-hardenable alloys are recommended to improve processing and final quality of the piece.

Production of wire: the basis for the production of chainware. In addition to great flexibility and softness, excellent solderability is a key element. Other uses of this semi-finished product must ensure toughness and ductility, especially for productions in very thin diameters and minimum grain size to prevent the phenomenon of orange peel.

Hollow jewellery: production of tube by means of TIG welding, or for the production of hollow chainware, or production of tubes from continuous casting. The characteristic feature of these alloys is a great resistance to thermal and chemical treatments.

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