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The first 126 MW gas turbine manufactured in China was the first of four 9E gas turbines that the South Steamship-GE complex won the bid in the national bundling tender. With the construction of the West-East Gas Pipeline Project and the development of the national economy, the gas turbine power station construction project has become China's key project dedicated to meeting the growing demand for electricity.
The ceremony was held at the South Steamship Factory. The National Ministry of Foreign Affairs (Li Ye, Deputy Director of the National Development and Reform Commission, President Lu Yanwei of the China Machinery Industry Federation) and Jiangsu Province (Deputy Governor Li Quanlin) and Nanjing (Executive Vice Mayor) Chen Jiabao) leaders attended the ceremony. The gas turbine will be transported to the Golmud Combined Cycle Power Plant in Golmud, Qinghai as part of a 200MW combined cycle power generation system.
The cooperation between South Steam Turbine and GE can be traced back to the early 1980s, when Nanqi Steam and GE cooperated to produce 6B series (42-46MW) gas turbines. Up to now, more than 60 sets of 6B series gas turbine sales contracts have been signed, of which 29 sets are exported, and the technical level is synchronized with the international level. The cooperation between Nanjing Steam Turbine and GE has provided a successful example for China to introduce and digest advanced technologies and comprehensively improve the manufacturing level of heavy gas turbines.
Under the organization of relevant ministries and commissions in China, in June 2004, Nanqi Steam and GE signed the 9E gas turbine technology transfer agreement, and then the two sides formed a consortium to bid for the China 9E gas turbine project and successively won the bid. On December 7, 2005, the Golmud project contract came into effect. On June 18, 2006, the first 9E gas turbine test station of the South Steam Turbine-GE Consortium successfully implemented the first ignition; on June 22, the whole machine passed the full speed. No-load performance test.
Shen Qun, general manager of the South Steam Turbine, commented: “The large-scale gas turbine is a major technological complete set of equipment developed during the 11th Five-Year Plan period in China. The first 9E gas turbine with a localization rate of 31.32% was completed and shipped, marking the South Steamship and The cooperation between GE and GE has reached a new height and has embarked on a road of cooperation, introduction, digestion and absorption, laying a good foundation for the rapid and healthy development of China's gas turbine industry."
GE is the world's leading supplier of power generation equipment, and the 9E grade gas turbine is a 50 Hz product that GE is widely used around the world. At present, GE has more than 382 installed 9E units worldwide, with a cumulative commercial operation time of more than 18 million hours.
“South Steamship has been working with GE for more than 20 years and is GE's earliest gas turbine manufacturer partner in China. The smooth assembly and delivery of the first 9E gas turbine fully reflects the partnership between GE and South Steamship. "This shows GE's long-term commitment and our local capabilities to provide China with reliable power generation products and technologies to support China's development and progress," said Wen Yuezhong, president of GE Energy China.
Submerged arc welding (SAW), as the name suggests, is conducted beneath a protective layer or blanket of flux. As the arc is always covered by the layer of flux, it eradicates any sort of radiation from the exposed arcs and also necessity of welding screens. With two variants of the process, automatic and semi-automatic, is one of the widely used welding process used in the process industry. Venus wire, one of the renowned Submerged Arc Welding Wire suppliers in India, illustrates the principle and uses of sub arc welding. Let us see them what they are:
Process:
Akin to MIG welding, SAW also employs the technique of formation of an arc between the weld joint and the continuous bare electrode wire. A thin layer of flux and slag are employed to generate protective gas mixtures and to add the required alloys to the weld pool respectively. As the weld proceeds, the electrode wire is released at the same rate of consumption and the excess flux is sucked out through vacuum system for recycling. Apart from shielding the radiation, flux layers also are highly beneficial in avoiding heat loss. The excellent thermal efficiency of this process, around 60%, is attributed to these flux layers. Also SAW process is absolutely free of spattering and does not require any sort of fume extraction process.
Operating procedure:
Alike any other welding procedure, the quality of the weld joints with respect to penetration depth, shape and chemical composition of the weld metal deposited are usually controlled by the welding parameters such as current, arc voltage, weld wire feed rate, and weld travel speed. One of the drawbacks (ofcourse methods are available to counter them) is that the welder cannot have a look on the weld pool and hence the quality of well is entirely dependent on the operating parameters.
Process parameters:
As mentioned earlier, it is only with the process parameters, a welder perfects the weld joint. For instance, in an automated process, the wire size and flux that employed that are suitable for the joint type, thickness of material, and size of the job plays an important role in deciding the deposition rate and bead shapes.
Wire:
Depending upon the requirement of deposition rate and travel speeds following wires can be selected
Twin wire
Multiple wire
Tubular wire
Metal powder addition
Single wire with hot addition
Single wire with cold addition
Flux:
Granular mixture of oxides of several elements such as manganese, titanium, calcium, magnesium, silicon, aluminium, and calcium fluoride are widely used as flux in SAW. Usually the combination is selected such that it provides the intended mechanical properties when it combines with the welding wire. It should also be noted that the composition of these fluxes play a vital role in the operating arc voltage and current parameters. Based on the welding requirement, primarily two types of fluxes, bonded and fused are employed in the process.
Uses:
Every welding method has its own set of applications, which usually overlaps due to scale of economy and quality requirement.
Although SAW can be very well employed for both butt joints (longitudinal and circumferential) and fillet joints, it has few minor restrictions. Owing to the fluidity of the weld pool, slag in molten state and loose layer of flux, butt joints are always carried out in the flat position and on the other hand, fillet joints are done in all positions – flat, horizontal, and vertical.
It should be noted that as long as proper procedures and selection of parameters for joint preparations are carried out, SAW can be successfully carried out for material of any thickness.
It can very well be deployed for carbon steels, stainless steels and low alloy steels and also few non-ferrous alloys and materials, provided the ASME code suggested combinations of wire and flux are used.
SAW finds a permanent place in heavy machine industries and ship building industries for welding heavy sections, large diameter pipes, and process vessels.
With very high utilization of electrode wire and easy automation possibilities, SAW is always one of the most sought after welding process in manufacturing industry.
Alloy Steel Submerged Arc Welding Wires
Alloy Steel Submerged Arc Welding Wires,Submerged Arc Welding Wire
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