Annealing Furnace

Annealing Gold, Silver, and Platinum In Jewelry Making

Annealing Furnace
Annealing Furnace

SuperbMelt annealing furnace is designed for annealing precious metal, such as gold, silver, and platinum in jewelry making. It works by the precious metal part is heated above the recrystallization temperature and then cooled after the material has been held at the desired temperature for a period of time.

The annealing process can improve the workability, mechanical properties and electrical properties of the workpiece metal. It goes through 3 stages, which are; the recovery , recrystallization and the grain growth stage.

The maximum power required for the metal annealing furnace is only 9kw, while the ammonia decomposition power is only 5kw. The machine adopts an intelligent PID temperature control device, which can work 24 hours and has an alarm function, effectively ensuring the safety and efficiency of the metal annealing process.

Why SuperbMelt Annealing Furnace

Professional R&D Team:
Over 15 years R&D experience in gold machinery with a top engineer team supported
High Quality:
Only choose famous brand main electric components for production
ISO CE SGS Approved:
Professional certification bodies certify that the machines are of high quality

    Any Question About SuperbMelt Annealing Furnace

    Guide of Annealing Gold, Silver, and Platinum In Jewelry Making

    Chapter 1:

    What Is Precious Metals Annealing?

    Annealing is said to be a treatment process focused on altering the physical and or the chemical properties of a given material. This alteration is intended to enhance ductility while reducing the hardness of the material so that it is easily workable.

    For the annealing process to work efficiently, the material must go above its recrystallization temperature for a given duration before being allowed to cool. The cooling rate varies based on the nature of the metal being annealed.

    This annealing method is suitable for precious metal jewelry manufacturing industries such as pure gold, silver, copper, K gold, copper alloy, 925 silver, etc.

    Chapter 2:

    What Is Work Hardening When Annealing Precious Metals?

    Work hardening, also known as cold hardening, refers to the situation that when plastic deformation occurs below the crystallization temperature, the strength and hardness will increase, while the plasticity and toughness will decrease.

    The occurrence of work hardening makes it difficult to reprocess metal workpieces. For example, when minting gold coins, gold bars, it will be too hard to press out a complete pattern. The effect of the design of bangles and beads will be very poor. Gold chains weaving also could not be completed.

    The annealing process is to improve the phenomenon of work hardening through heat treatment. The metal is heated to a certain extent and cooled at a suitable temperature, which reduces the hardness and makes the metal workpiece soft and bendable, so that the rolling sheet, wire drawing, and chain making process can be done easily.

    Chapter 3:

    How to Anneal Precious Metals?

    Metals are oxidized during annealing heat treatment, so annealing must continue in the process of oxidation until the metal turns red. It should be noted that when the metal turns dark red, the critical temperature is reached, and the heating needs to be stopped immediately. Otherwise the metal may be melted.

    Then followed by quenching, which means that the heat-treated metal is cooled in water to the extent that it can be reworked. A piece of metal can be annealed multiple times, and the degree of annealing is controlled as long as it can ensure that the metal will not become very hard during the reprocessing process, can support the modeling operation and will not dry out.

    It is easier to master the annealing technique through experience. If you are a newcomer, we will also provide some detailed data for your reference.

    3.1, How To Anneal Gold?

    For gold of different purity and form, the annealing time and temperature are different. For gold of different shapes, we also need to use the correct method to deal with it.

    • Yellow and White Gold Alloys

    The degree of annealing of gold alloy is basically heat treatment at 676℃ for 10 minutes to light red, and then water quenching.

    Platinum alloys need to be heated at 732℃ for 10 minutes to dark orange before water quenching.

    • Thick and Thin Lines

    Both gold thick and thin wires should pay attention to the adjustment of temperature and time. The temperature must be lower than the melting point of gold. When heating, turn the workpiece to make it evenly heated. After turning red, put it in water to quench. For thin wire annealing, when winding the coil, pay attention to plugging the two ends to fix the whole coil to prevent it from spreading out during heating.

    • Sheets and Blocks

    For gold sheet and bar, we developed a special tunnel furnace, which is more suitable for manufacturers with mass production needs, and it has a welding function. When the welding auxiliary material is placed between two metals, it can help the two workpieces are connected in the heating process. and the annealing process realizes welding at the same time, which makes the work more efficient.

    3.2, How To Anneal Silver?

    Even without annealing, since the hardness of silver itself is not very high, it can reach 70% cold working.If sterling silver is annealed, it needs to be heated to 593°C to turn dull red, then quenched in water.

    It should be noted that the annealing of pure silver needs to be done in conjunction with protective non-oxidizing materials. After the annealing is completed, put the silver workpiece into the pickling solution for a few minutes to remove the protective material.

    3.3, How To Anneal Platinum?

    The annealing temperature of platinum needs to reach 982°C. After it turns bright orange, the platinum workpiece can be cooled naturally or in water. Due to the nature of platinum, 70% cold work can be achieved before annealing.

    For the annealing of platinum alloys, such as 950Pd and 950Pt, it can be heated at 982°C for about 15 minutes then quenched.

    3.4, Common Problems Encountered in Precious Metal Annealing?

    When should precious metals be annealed?

    • When your next step involves drawing the metal into wires, rolling sheets, etc. that need to change the material, annealing will facilitate the forming of the metal, and there will be no problem of dry cracking.
    • If the metal needs to be bent and forged. Annealing softens the metal and makes it easier to shape.

    How to adjust the flame size of annealing?

    The flame usually needs to be large and soft. When annealing precious metals with good thermal conductivity, increase the flame according to the size of the workpiece, so that the heating will be more sufficient.

    Chapter 4:

    Why Choose SuperbMelt Annealing Furnace

    SuperbMelt is your number one stop for all your annealing needs. Note that besides providing some of the best annealing furnaces, we can help you with the work on-site.

    Better still, if you choose to purchase any of our products, we will supply you with a comprehensive manual to enhance your experience. At the time of writing this guide, from us, you can get an annealing furnace that comes in a compact design, with a range of features that you will find useful.

    Before we delve deeper into this section, it is vital to understand that SuperbMelt has a wide range of annealing surfaces. We will mention some of have mentioned them in the next section of this chapter.

    4.1, Types of SuperbMelt Annealing Furnaces

    We have annealing furnace and mesh belt furnace. Both of them are all designed for professional precious metals.

    Their application is easy, but we will be there for you every step of the way to see that you have the best user experience with our products.

    The SuperbMelt annealing furnace is creatively designed to heat metals above recrystallization temperature. Once the desired temperature has been achieved and maintained for some time, the furnace will cool back the metal so that the necessary results are achieved.The entire annealing process is carried out under the protection of ammonia gas, so that the workpiece will not be oxidized and retain the original color.

    With our furnace, you will enjoy enhanced machinability and electrical and mechanical properties of your workpiece metals.

    For instance, with a maximum power of 9kw, with ammonia decomposition of around 5kw, you will achieve a lot.

    4.2, What is the Working Principle of SuperbMelt Annealing Furnace?

    SuperbMelt annealing furnaces use electric power to heat workpieces to the desired temperature and cool them back. Without consuming too much power, the furnaces leverage unique features to ensure that the working surfaces don’t get oxidized.

    After the entire process is completed, you will end up with a ductile workpiece that can be used for a range of applications without developing internal stress. The entire process doesn’t take too long, so within a day, you can get a lot of work done without sacrificing quality.

    Recrystallization is a process that is accompanied by the reduction in hardness and strength of the material while ensuring a significant increase in ductility

    4.3, Technical Specification Difference of SuperbMelt Annealing Furnaces

    For a clear presentation of this crucial information, we have shared the specs of the two machine separately. Let us begin with the Annealing Furnace:

    • Model number-SPB-TF
    • Power-9kw
    • Ammonia decomposition power-5kw
    • Heating time-40-60 minutes
    • Maximum temperature-1100 degrees centigrade
    • Used gas-ammonia
    • Working slot width -850*1400*1600mm (W*L*H mm)
    • Weight-135kg

    Annealing Furnace

    Below are the specs for the Mesh Belt Furnace:

    • Model number-SPB-AWF
    • Power source-3 phase 380V, 50/60Hz
    • Power-13kw
    • Maximum temperature-950 degrees centigrade
    • Speed-sleepless speed regulation
    • Cooling way-water cooling
    • Used gas-Ammonia
    • Working slot-70*40 (W*L mm)
    • Network bandwidth-50mm
    • Dimension-3000*600*1500 (W*L*H mm)

    mesh belt furnace

    4.4, What are The Advantages of SuperbMelt Annealing Furnace

    Unlike the other furnace, our mesh belt furnace is divided into two integral parts. The left side contains the furnace chamber ammonia flowmeter, while the right chamber contains the cooling water ammonia flowmeter.

    To run this furnace, you will need to supply it with a maximum power of 13kw and a maximum temperature of 950 degrees centigrade. This furnace is specifically designed for the hardware industry, more so for the jewelry-making companies.

    It is also made for the coin bar minting industry. It can be used on silver, k-gold, and cast iron workpieces. This explains why it comes with a wide range of features and uses slightly high electric energy.

    The combined frame of the furnace is not hard to install and can also be dismantled in seconds. The features are also well designed so that they can stand some rough handling.

    Your furnace will come with some purification device of nitrogen that is produced through ammonia decomposition. SuperbMelt is an annealing furnace manufacturer, and our products come with a temperature regulator, timing setter, cooling chamber linear regulator.

    The furnace also leverages a speed regulator for the mesh belt. This ensures excellent perfect control and efficiency in the workplace. With the timing setter control, you can schedule automatic annealing, which means you will have some time to focus on other important things.

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