[Nikkei BP News Agency] At the "24th Japan International Machine Tool Show (JIMTOF2008)" (Tokyo Ariake International Convention and Exhibition Center) on November 4, 2008, major superhard tool manufacturers introduced waste Measures for tool recycling. In the case of a surge in the prices of raw materials such as tungsten (W) and cobalt (Co), the recycling business has attracted considerable attention as a measure to stabilize the procurement of raw materials.

Mitsubishi Materials introduced the recycling business that began in March 2008. The company's technology is characterized by the "complete oxidization" of used superhard tools through a method called "oxidation roasting". Specifically, the waste superhard tool is oxidized, pulverized, and then immersed in a solvent to separate ammonium paratungstate (APT), cobalt, and titanium used for the surface coating, and then sent to different recycling processes according to the material. The APT is oxidized again to become tungsten trioxide (WO3) from which tungsten carbide (WC) or tungsten can be extracted. From about 125 kg of used tools, about 100 kg of tungsten can be extracted. These tungsten are all non-impurity materials and can be reused directly as a raw material for superhard tools (Figures 1-6). In addition to tungsten, 27 materials can be recycled and reused.

Mitsubishi Materials has established a tungsten powder factory in the Akita Plant (Akita City), a wholly-owned subsidiary of the company and a refining tungsten plant in Japan (Mitsubishi Materials), a new metal (headquarters: Osaka City) plant. To promote the recycling business. The current recycling rate of used tools is around 10%, but the company plans to increase to 50% by 2012.

One of the reasons the company is doing this business is the surge in tungsten prices. Most of the tungsten used in Japan is imported from China, and the price of tungsten has increased 7 to 8 times in 10 years. Through the recycling business, raw materials can be stably obtained. Another reason is the quality issue. China originally exported tungsten in the form of APT, and the recent export to WC has increased. However, the quality of using this WC as a raw material for superhard tools is not good, so the best way to get high quality WC is through recycling.

In addition to Mitsubishi materials, Sumitomo Tool Net (headquarters: Osaka City) is conducting research on extracting WC by chemical treatment. Since the 1980s, the company has been working on the recycling of super-hard tools through the “zinc treatment method”. Compared with chemical treatment, this method has the advantage of being completed only by small-scale equipment and reducing the processing cost. However, the recycling must be subdivided and the quality of the obtained tungsten is limited.

The advantage of chemical treatment is the availability of high quality tungsten. However, the treatment process requires the use of a large number of chemical agents, and there are problems such as a large environmental load. In response, the company's goal is to develop new processes that reduce environmental loads and energy consumption when recycling APTs. In July 2007, the research was adopted as a commissioned research project for the “Energy Utilization Rationalization, Rare Metals and Other Efficient Recovery System Development Business” by the Oil and Gas Metal Mineral Resources Agency (JOGMEC) (see this site report). The company is still working on zinc treatment.

According to the Superhard Tools Association, the global consumption of tungsten is 70,000 tons per year. Through the US Mineral Resources Survey, the current confirmed reserves are only 2.9 million tons, so countries are giving priority to ensuring domestic use, and it is difficult for Japan to ensure stable supply. In the future, in order to stabilize the supply of tungsten, it is necessary to increase the recovery rate. At present, the recycling rate of used super-hard tools (chips) is about 40% in Europe and America, and only about 20% in Japan.

  

DUPLEX STAINLESS STEEL

Duplex Stainless Steels Available

Yuhong Group supplies LDX2101, 2205, Ferralium 255, Zeron 100 and LDX2507 in the form of plate, sheet, strip, bar, pipe, tubing, pipe fittings, flanges and weld wire.

Duplex Stainless Steel Overview

Duplex Stainless Steels, also referred to as austenitic-ferritic stainless steels, are a family of grades with about equal proportions of ferrite and austenite. These steels have a duplex microstructure which contributes to their high strength and high resistance to stress corrosion cracking. Due to their high content of chromium, nitrogen and molybdenum, duplex steels offer good resistance to local and uniform corrosion. Duplex stainless steels have good weldability.

Today, modern duplex stainless steels can be divided into three groups:
Lean Duplex such as LDX2101
Standard Duplex such as 2205, the work-horse grade accounting for more than 80% of duplex usage
Super Duplex such as Ferralium 255 and Zeron 100 and LDX2507

Of the duplex grades, duplex 2205 is the most widely used. However, the super duplex steels like Zeron® 100 and LDX2507 are excellent for servicing severe corrosive environments, such as offshore and marine applications. Lean duplex 2101 is available as an economic alternative to 300 series stainless steels.

What are the Characteristics of Duplex Stainless Steels ?
Very good resistance to uniform corrosion
Very good resistance to pitting and crevice corrosion
High resistance to stress corrosion cracking and corrosion fatigue
High mechanical strength
Good sulfide stress corrosion resistance
Good abrasion and erosion resistance
Good fatigue resistance high energy absorption
Low thermal expansion
Good weldability

In what Applications are Duplex Stainless Steels® used ?
Oil and gas equipment
Offshore technology
Seawater desalination plants
Chemical industry, especially when handling chlorides
Flue-gas cleaning
Desalination plants and seawater systems
Pulp and paper industry
Cargo tanks and pipe systems in chemical tankers
Firewalls and blast walls on offshore platforms
Bridges
Storage tanks
Pressure vessels, reactor tanks, and heat exchangers
Rotors, impellers and shafts

Duplex Steel Flange

Duplex Steel Flange,Duplex Stainless Steel Flange,Super Duplex Steel Flange

YUHONG GROUP CO.,LIMITED , http://www.jessro-pipefittings.com