Monday, 17 July 2017

MICROWAVE WELDING

In the field of joining of metals research are taking place for innovative ideas to come. One such new idea is microwave joining. It is one of the newly developing and advanced technique. But the thing is most people are unfamiliar with this type of process. It is a kind of fusion welding using frequency of 2.54 GHz. Microwave technique uses microwave energy which interacts with the material at the joint interface. It can be transmitted, reflected or absorbed when interact with materials. For processing materials like glazing of sprayed ceramic composite surfaces microwave energy can be used.
Microwave energy is widely used in composite and ceramics because of its nature. The nature of composite and ceramics is that they absorb microwave. As metals tend to reflect microwave radiations less work is done in the field of metals. This method was experimented on mild steel and stainless steel as substrates. For joining butt joint is preferred as it is easy to handle. Substrates are surrounded by refractory brick after applying the interfacing material between the faces. When microwave comes in contact with charcoal, which is used to provide extra heating, it starts burning thus increasing the temperature at the joint. The faces of substrates get totally wet. The molten region coverts into a shape of joint after cooling at atmospheric situation.

Taguchi method was developed by Dr. Genichi Taguchi to improve the quality of manufacturing goods. It is also applied in engineering field. The quality engineering set by Dr. Taguchi in 20th century was regarded as greatest achievement in engineering. In his concept he mainly focuses on engineering strategies which includes upstream and shop-floor quality engineering. In upstream method small-scale experiments and robust designs for large scale production is used while cost based real time system is used in shop floor technique. Three concepts where there in Taguchi’s philosophy. One was that quality should be planned into the manufactured goods. Best worth is achieved by reducing the deviation on or after the target. This was his second. The expenditure of quality should be calculated as a function of deviation from the standard and the losses should be measured system-wide was his third.
After doing the Taguchi’s method using L9 orthogonal array some results were obtained. The value of hardness is lower at 600 sec as the material doesn’t fuse properly than 700s and 800s. There is decrease in hardness due to excessive heat at 800s. The percentage of interfacing powder will result in proper fusion and less porosity will be observed. Since the hardness of the stainless steel base metal is higher than mild steel base metal the SS-SS joint has higher hardness. Among the three parameters, substrates has the major influence on the hardness followed by percentage Ni based powder used and time. Like that new technologies and ideas are coming in the field of welding and inspection. welding inspector course in kochi

Friday, 7 July 2017

SURFACE MODIFICATION OF MARTENSITIC STAINLESS STEEL

    It is a common practice in various engineering applications to modify the surface properties of material requiring specific surface characteristics of any component over that of its core material to suit various service conditions. It is most commonly achieved by modification of physical, chemical, mechanical and metallurgical characteristics of the surface of a metal. There are many sophisticated treatment like sputtering and treating by plasma, laser, ion and electron beam but surface modification is commonly carried out by mechanical treatment, heat treatment and fusion of the substrate as well as extra deposition on it. From the experiments done it is derived that surface fusion by gas tungsten arcing can be precisely applied for appreciable surface modification up to significant depth of a metal substrate. One effective method to achieve desired micro structural transformation is gas tungsten pulse arcing (GTPA). The precisely controlled thermal distribution in the arcing system makes it suitable for this process.

   
     GTPA due to its high peak current compared to GTA can be operated at higher energy input. But due to lower mean current, net heating of the base material remains lower. Thus by using GTPA better heat control along with wider fusion zone and larger depth of penetration is achieved. The GTPA has the ability to control energy input as well as its distribution in the entire process of surface modification of the substrate by fusion. It is achieved by manipulation of the solidification behavior and nature of phase transformation in the matrix through a control over the depth of fusion.

    The surface modification process on annealed 5mm thick stainless steel gave some results. It was carried out with the help of a Fronius Magic wave 1700 pulsed TIG welding machine. The characteristics of ripple in fusion zone were examined for different f and ᶲ values. It was observed that more number of ripples are formed per unit length with the increase of either f or ᶲ. This has resulted in relatively finer surface ripples at higher f and ᶲ. The cooling rate and solidification behavior of fusion zone have been analyzed. It has been observed that there is significant increase in cooling rate as well as primary solid growth rate for both cases that is increasing ᶲ and maintaining f constant and increasing f and maintaining ᶲ constant. Comparatively larger time for heat dissipation in between pulsed arcing at low frequency is reason for the relatively low cooling rate at lower f. it reduced the temperature gradient of fusion zone to its relatively large area of hot surrounding heat sink. A relative lowering of fusion zone width with decrease of ᶲ from 0.3 to 0.25 may have happened due to some predominant compromising effect of ᶲ in reduction of heat buildup in fusion over the effect of f on enhancement of the same up to certain extent. The controlled fusion by gas tungsten pulsed arcing and its consequent thermal behavior has significant effect on the microstructure of fusion zone and heat affected zone. The change in cooling characteristics of the matrix during solidification of the fusion zone is the reason for hardness increase. Welding inspector courses in Ernakulam

Saturday, 1 July 2017

WELDING OF ULTRAHIGH STRENGTH STEEL

Structural steels with very high strength levels capable of developing minimum yield strength of nearly 1400 MPa is called ultrahigh strength steels. In recent times, the ultrahigh strength steels are in a great demand for critical structural aircraft and aerospace application. In aircrafts, automobiles, power plants, chemical industries etc. for technical as well as economic reasons the dissimilar combination of steels are necessary. Maraging steel and medium alloy medium carbon steel are used in these situations. Maraging steels are a class of precipitation hard enable martensitic steels. It develop strength due to the precipitation of inter metallic compounds.

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Fabrication process which is widely employed for ultrahigh strength steels is fusion welding. Gas tungsten arc welding and electron beam welding are the two fusion welding employed. Three types of filler materials are used which include maraging steels filler, austenitic stainless steel filler and medium alloy medium carbon steel filler. The austenite get transformed to martensite during cooling in the fusion zone in maraging steels welds. In medium alloy steel weld the columnar grain growth is prevalent at the center. After post weld aging no variation is observed in microstructure as compared to as welded condition in respect of austenite stainless steel and medium alloy medium carbon steel filler welds.
The hardness survey was done on different filler welds. Austenite stainless steel weld metal shows the lowest hardness. The region of weld of medium alloy medium carbon steel filler shows the highest hardness. The hardness of maraging steel filler weld is as likely as parent metal. The residual stress at the center of the weld metal zone is compressive in case of maraging steel and medium alloy medium carbon steel weld metals. When it comes to the case of austenite weld the residual stress at the center of the weld metal zone is tensile. welding inspection courses in Kochi.
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The similar metal welds will show symmetrical fusion zone and heat affected zones, whereas the dissimilar metal welds shows un symmetrical fusion zone and heat affected zones. The difference in the thermal conductivity of materials is the reason for the unsymmetrical nature. In medium alloy medium carbon steel the width of heat affected zone is more when compared to maraging steel. The residual stress in similar metal weld of maraging steel is compressive and in similar metal weld of medium alloy medium carbon steel it is tensile. In case of dissimilar metal weld it is compressive in maraging steel and tensile in medium alloy medium carbon steel.

Friday, 23 June 2017

PLASMA GOUGING

    Welding process and welding engineering came into its own in early 19’s. It was at the time of World War II that welding processes got a new face. Today welding has turned to vital field where lots of career opportunities in it. Welding process or technology had gone through different phases and evolved from a trade to science. Traditional methods got modified during this period of time. In the last 10-15 years plasma gouging became a viable solution. In 1940s the gouging was done using carbon arc with help of welding machine and a carbon electrode to melt metal. The metal part of surface is melted or removed and a gouge or groove is fumed on it. Many types of gouging like oxyfuel gouging, air carbon arc gouging mechanical gouging exist in this field.

    In plasma air gouging smooth and clean grove is obtained. The main advantage that this method provides is that, it is smoke free and also quiet operation. A correct knowledge about the working of this technology and scope of being merged with application based solution is necessary for growth of implementation of the technology.
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    Defining the gouge is basic of plasma gouging. For each operation gouge varies according to the application. A gouge which is ideal for one operation may not be ideal for another application. Quality of gouge is another parameter in plasma gouge. Factors that makes a gouge perfect is, whether the operation the operator removed correct amount of material from the surface and also it should be in correct controlled manner. Shape in some case plays vital role in other case may not be crucial.

    The removal of part can be categorized into two ways, positive feature removal and negative feature removal. The positive feature removal refers to the removal of those part above the surface i.e. it will be in space and will not be covered by other material. The negative feature removal refers to removal of part surrounded by other material. Seized bolt removal which is also called nut removal, casting sprue removal, protruding surface features removal such as fillet weld comes under the positive surface feature removal. The excavation of weld defect, spot weld removal and back gouging comes under negative feature removal.
    
    In negative feature removal, the gouge profile is more important. It is crucial than the rate at which one can remove material. Few assumptions are done regarding gouge profile like relation between width and depth of gouge i.e. width of gouge should be greater than its depth and profile should be maximum symmetrical.
The ionized gas which are electricity conductive is super-heated to obtain plasma. The velocity and energy density is increased by constricting its cross section area. Supersonic speeds are achieved. These parameters are varied to obtain different bore design. When the area become more constricted velocity increases and its cutting capabilities are also increased. These factors are combined to produce partial melting and effective subsequent clearing of slag.
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    The system amperage and angle of torch are other features that influence plasma gouging. The gouge depth is proportional with amperage. The depth of gouge is increased as amperage increases. The angle of torch influence the gouge shape. A primary angle is given to make basic gouge shape then another, a second angle is given to increase the width of gouge. This process is called offset angle gouging. When angle is zero it is straight line gouging. As angle increases gouge get wider. As angle approach 90 profile become asymmetric shape. WQC NDT Institute provides welding inspection courses in Kochi.
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Thursday, 19 January 2017

Oil andGas industry has a huge workers shortage of 100,000 in coming year


US oil and gas industry will be needed of ten thousands of employees in the coming two years as the oil price is recovering and more rigs being explored. In last week government data showed that US has a whopping 287,000 jobs in coming June, and country’s unemployment rate was below 5 percent.
As the oil field has been emerging up there will be shortage of mid-career workers as like in 1980s. In that type of situations since the service company is having shortage in workers, they may have to pay politely to them. 


In the earlier 2014’s there had a severe job loss, so they have concentrated for the related industries for the sustainability. But the talents exit from the oil and gas the industry permanently, since this happened the long term shortage of talented workers are growing up.

As per the studies, the high pay in oil and gas industry makes United States possible to attract its subsidiary and service companies which in turn make employment vacancy of 80,000 – 100,000. In most of the companies they have retained their experienced staff fleets by some salary decrements or placing them in low rank, so can give them  promotion when the oil price get recovered and activity get increased.
If this is the condition as per the whole predictions, all companies have to hire the individuals and provide them with the training skill for make them employable.
One more positivity for the people is that the industry hasn’t done any new hiring for last two years. At the same time, enrollment in petroleum engineering programs across US was falling. Secondly, a large number of experienced and high income workers have retired or gone out of the industry leaving a large opportunity for the middle level employers to fill the skills gap.

Thursday, 28 April 2016

Admission Started for Best QA,QC Training in kerala

WQC Institute of NDT and Inspection Technology Ernakulam is one of the best  institutes that provides QA/QC&NDT training in Kerala.There are many openings in the field of QA/QC&NDT in the industry.The need of QA/QC&NDT Experts will not decline in the industry.
COURSES OF WQC NDT:


Quality Control Inspection Courses

•Certification Course For Welding Inspector

•Certification Course For Painting Inspector/QC Technician/Painting Supervisor

•Certification Course For Welding Foreman/Supervisor

*Those who have completed the above 2 courses are only eligible to attend this course

ASNT NDT Level I/II (Corporate Partner of ASNT)

•Radiographic Testing

•Ultrasonic Testing

•Magnetic Particle Testing

•Liquid Penetrant Testing

•Radiographic Film Interpretation

•Visual & Optical Testing

Diploma Courses(6 MONTHS)

•Diploma in Welding Inspection

•Diploma QA/QC Inspector

•Welding courses ( SMAW(MMA), TIG(GTAW), MIG/MAG(GMAW))

•Course Modules: 1F,2F,3F, 4F, 1G,2G,3G,4G,5G,6G & Allied training Gas cutting,Gas welding, Beveling, Gouging

Welding Courses

•SMAW Entry Level

•SMAW Advanced Level

•GTAW

•GMAW

•FCAW

•Gas Cutting

•Gas Welding

•Air-Carbon ARC Gouging

Lead Auditor Courses

•Quality Management System

•Enviornment Management System

•Occupational and Safety

•Food Safety Management

•Information Security

Piping Engineering

•Awareness program on all Piping components

•Drawings (ISOMETRIC, P&ID, GENERAL ARRANGEMENT DRAWING)

•Codes, Standards and Specifications (ASME,API,ASTM,AWS) etc.


For more details contact:
WQC Institute of NDT and Inspection Technology
Arjun Tower,cusat road,cusat PO kalamassery
Ernakulam-682022


Wednesday, 30 March 2016

Structural Engineering



Structural Engineers are prepared to comprehend and ascertain the solidness, quality and unbending nature of assembled structures for buildings and non building structures, to create plans and incorporate their configuration with that of different planners, and to administer development of undertakings on site. They can likewise be included in the outline of hardware, medicinal gear, vehicles and so forth where basic uprightness influences working and security. 

Structural Engineering hypothesis is based upon connected physical laws and experimental learning of the basic execution of various materials and geometries. Auxiliary designing outline uses various generally straightforward basic components to manufacture complex basic frameworks. Basic specialists are in charge of making innovative and effective utilization of assets, basic components and materials to accomplish these goals.