China-South Korea after signed FTA, up to 20 years, China zero-tariff products will achieve up 92% of tax items and achieve up 91% of imports. Korean and China 90% products tax items and 85% trade volume all achieve linearization, namely the tariff is zero. China to reduce some clothing, footwear, skin care products, diapers and other consumer goods import tariffs and the average range fell more than 50%. The agreement covers trade in goods, services, investment and rules, a total of 17 areas, including the e-commerce, competition policy, government procurement, environment and other 21st century economic and trade issues. In terms of tungsten products, South Korea imported tungsten products form China can enjoy most-favoured-nation clause and the tariff of tungsten products reduced by 5%.

MFN is an important provision of trade treaty, which refers to contracting party A present and future giving all the privileges, concessions and exemptions to any third party and should give to the contracting party B. The MFN principle requires members to grant each other most-favored among parties, namely the GATT contracting principle is: a member of the trade preferences and licensing another party member must be automatically extended to all other members. As the basic and the most important principle of GATT, the MFN principle to regulate trade in goods between the members of the party, to promote the expansion of international trade and development played an important role.

The treatment range of MFN is large, and the most important is tariff treatment of the major import and export commodities, including imports, exports or transit goods and other taxes; there are some strict customs regulations, procedure and fees about merchandise import, export, transit, warehousing and change ships. In the Treaty of Commerce and Navigation, the scope of the MFN clause applies even bigger, the contracting state into the ship and its cargo, and pulled out all kinds of taxes, fees and formalities at berth are included.

China tungsten carbide industry has 60 years of development history, which has been regarded as a big country of carbide. According to carbide branch of CTIA (China Tungsten Industry Association) statistics, the last three years (2012-2014) of the annual output of domestic carbide 2.2-2.5 million tons, which more than 40% of global output. Although the production and consumption of tungsten carbide of our country is at the leading place around the world, as far as the level of manufacture and technology, we still fall behind. In terms of the plateau of domestic tungsten carbide industries development, we developed many research projects and establish a special carbide R&D team, after more than ten years of basic research and technology development to study ultra-fine carbide nano-scale manufacturing equipment and engineering application of a series of new technologies, and work closely with companies to develop over carbide materials and high value-added products toward high-end applications development.

For WC-based tungsten carbide, compared with conventional coarse grain (the average grain size about 13μm), tungsten carbide with ultrafine grain (the average grain size about 200-500nm) and nano grain (the average grain size lower than 200nm) has high hardness, high strength, high fracture strength and excellent wear and corrosion resistance, which becomes the indispensable material for drilling, cutting and milling process. Since late 1990s, nano tungsten carbide has been emerged many new processes. In recent years, ultra-fine carbide and nano-scale preparation and industrial applications become international attention, reflecting the forefront of competitive research focus, which experienced a period of many preparation methods of nano carbide change of evolution. Such as sol - gel / co-precipitation method, a plasma method, but they are limited to use in nano WC powder synthetise in laboratory; spark plasma sintering, high pressure and so consolidation is limited to the preparation laboratory simple shape and small three-dimensional nano-polycrystalline material; Complex spray conversion method steps, the high cost of the process, demanding precision control, which greatly limits the technology in the manufacture of nano-WC-based powder application.

Chinese R&D team in tungsten carbide has a breakthrough in the research and development of high-performance tungsten carbide composite material, it mainly includes:

1. Phase controlled particle size adjustable nano WC-Co composite powder scale preparation techniques: It takes tungsten-cobalt oxide and carbon as raw material, and uses solid-phase synthesis in-situ reaction to synthesize ultrafine or nano WC-Co composite powder. It has many advantages, such as simple operation, short process, Low-cost equipment, energy saving and so on. The synthesis of composite powder has high purity, low oxygen content, Co content within a wide range of 6-20wt% is accurate and adjustable, which reached on the current international quality ultrafine nano WC-based powder control standards.

2. High liquidity, nano-structure WC-based spraying powder scale preparation techniques: It based on the principle of spray-drying and combines with heat treatment, which not only maintains the characteristics of nano structure, but also can fabricate the thermal spray powder with high fluidity. So it gets to the root of nano powder thermal spraying at high temperature flame flow easily decomposed decarbonization, which is a difficulty in international technical fields.

3. High density, high surface quality and technical preparation of carbide wear and corrosion coating: The technology synergistically adjust the initial powder component, thermal spray granulation and agglomeration process, by a combination of carbon content design, unique heat treatment process, recombinant size, thermal spraying process parameters optimization to fabricate high-performance nano-structure carbide coating. The coating having a porosity of <0.5% of a high density; compared with the conventional micro structure, the surface quality has significantly improved, the surface roughness Ra <0.5m.

4. Ultrafine size nano-crystalline tungsten carbide block preparation: The technology develops a low-temperature region slow heating rate, low pressure, high temperature rapid heating region segmentation, greater pressure, does not heat the unique field effect sintering process. And produces nano tungsten carbide block with average grain size of 60-100nm. The average grain size of 60nm dense nano-crystalline alloy is the smallest grain size reported so far around the world. Meanwhile, nano-crystalline tungsten carbide sintered material can meet the requirements of high hardness and high fracture toughness.