Гричин С.В., Ульянова О.В. - Английский язык для инженеров сварочного производства (1044906), страница 17
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The weld map would also usually have somespace for approval, either weld by weld, or once a project or structure hasbeen completed. The Figure below shows a detail of a typical weld map for afabricator in the power generation industry.Data are usually entered into the system from four functions, asfollows:93At the design stage, where information such as the weld ID numberand other design parameters (material type, thickness, joint type, etc.) areentered.At welding engineering, where a procedure is assigned. It may also bepossible to identify suitable welders or classes of welders qualified to makethe weld, although this is more likely to be done at the production stage.
Atproduction, where the completion of a weld is registered (usually by enteringthe date) and visual inspection carried out and approved.The system also gives instant progress reporting. Anyone with accessto the system can see how fabrication is progressing. This may be simply bylooking at the weld data sheet on screen or by explicitly programmedprogress reports.
These can identify bottlenecks (by, for example, comparingthe number of welds competed with the number of weld radiographed), orhelp to produce reports for stage payments in large projects.It also provides automatic assignment of welding procedures andwelder. If enough information is supplied at the design stage, the systemsearches through a database of procedures for suitable welding procedurespecifications (WPSs).
This may be a single WPS of a number from which tochoose from, with a click of a mouse button. Having chosen a suitable WPS,the system searches through WPQs for qualified welders. If necessary, thesystem can list welders in order of their certificate expiration dates; withthose due to expire soonest at the top of the list; so maximum benefit can bemade of extending their qualification.The system can also produce reports on repair rates per welder (toidentify training requirements), by procedure (to highlight defect-proneprocedures) or by any other measure, providing the relevant data arerecorded.It also automatically generates document packs on completion of aproject. A very time-consuming task manually, it's again ideally suited forcomputerization.
With the click of a button, the system can print the weldmaps for a project, along with all the WPSs used (with backup procedurequalification records (PQRs) if necessary and all the WPQs, which areupdated automatically based on satisfactory production welds. In addition, ifNDE specifications have been used to report testing, the system can printrelevant NDE reports as well. This information can also be archived on CD.It can also instantly trace production welds to the information backingthem up.
If the inspector wants to see a WPS that was used on a weld, orproof that the welder was suitably qualified, this can be done with the click ofa button. This can be especially useful while inspection a structure after anumber of years of service. If a defect is found, the engineer can access the94original WPS, for repair purposes, or the NDE report, to see if evidence ofthe defect was present at testing.Vocabularystoragedatabasefiling cabinetpower generationbottleneckхранениебаза данных1) шкаф для хранения документов; 2) картотека,каталогпроизводство электроэнергииузкое место19Make an abstract of the two parts of the article Moving WeldManagement from the Desk to the DesktopRevision20Make a short description of Friction Stir Welding method using thefollowing key words.Fusion, filler material, aluminium and its alloys, plates and sheets, frictionalheating and mechanical deformation, rotating tool, tool, shoulder, pin, workpiece, heat generation, microstructure of a friction-stir weld, applied pressure,characteristics of the material, withdrawal of the tool, onion-ring structure,HAZ, integral weld.95PART 6.
HEALTH, SAFETY AND ACCIDENT PREVENTIONLead in1Discuss in the group.1. Do you think welding is a dangerous/hazardous profession?2. What type/types of welding do you consider the most/least hazardous?Why?Reading 12Look through the text Health Risks of Welding Fume/Gases and listthe risks generated during welding.Health Risks of Welding Fume/GasesWelding fume is a mixture of airborne fine particles.Toxic gases may also be generated during welding andcutting.Particulate fumeMore than 90 % of the particulate fume arises fromvaporisation of the consumable electrode, wire or rod asmaterial is transferred across the arc or flame. The range ofwelding particles size is shown in relation to the more familiar types of dustand fume. The respirable fraction of particles (especially less than 3µm) arepotentially the more harmful as they can penetrate to the innermost parts ofthe lung.GasesGases encountered in welding may be:- Fuel gases which, on combustion, form carbon dioxide and, if the flame isreducing, carbon monoxide;- Shielding gases such as argon, helium and carbon dioxide, either alone or inmixtures with oxygen or hydrogen;- Carbon dioxide and monoxide produced by the action of heat on thewelding flux or slag;- Nitric oxide, nitrogen dioxide and ozone produced by the action of heat orultraviolet radiation on the atmosphere surrounding the welding arc;96- Gases from the degradation of solvent vapours or surface contaminants onthe metal.The degree of risk to the welder's health from fume/gases will depend oncomposition, concentration, the length of time the welder is exposed, thewelder's susceptibility.Health hazards from particulate fumeThe potential hazards from breathing in particulate fume are:1.
Irritation of the respiratory tract. Fineparticles can cause dryness of the throat, tickling,coughing and if the concentration is particularly high,tightness of the chest and difficulty in breathing.2. Metal fume fever. Breathing in metal oxidessuch as zinc and copper can lead to an acute flu-likeillness called 'metal fume fever'. It most commonlyoccurs when welding galvanised steel; symptomsusually begin several hours after exposure with a thirst, cough, headache,sweat, pain in the limbs and fever. Complete recovery usually occurs within1 to 2 days of removal from the exposure, without any lasting effects.3.
Longer term effects. The continued inhalation of welding fumeover long periods of time can lead to the deposition of iron particles in thelung, giving rise to a benign condition called siderosis. There is evidence thatwelders have a slightly greater risk of developing lung cancer than thegeneral population. In certain welding situations, there is potential for thefume to contain certain forms of chromium and/or nickel compounds substances which have been associated with lung cancer in processes otherthan welding. As yet, no direct link has been clearly established.Nevertheless, as a sensible precaution and to minimise the risk, specialattention should be paid to controlling fumes which may contain them.Additional hazardsA number of other specific substances known to be hazardous to healthcan be found in welding fume such as barium and fluorides which do notoriginate from the metal.
If the metal contains a surface coating, there willalso be a potential risk from any toxic substances generated by thermaldegradation of the coating.97Health hazards from gasesThe potential hazards from breathing in gases during welding are:1. Irritation of the respiratory tract. Ozone can cause delayedirritation of the respiratory tract which may progress to bronchitis andoccasionally pneumonia. Nitrogen oxides can cause a dry irritating cough andchest tightness.
Symptoms usually occur after a delay of 4 to 8 hours. Insevere cases, death can occur from pulmonary oedema (fluid on the lungs)or pneumonia.2. Asphyxiation. There may be a risk of asphyxiation due toreplacement of air with gases produced when welding in a workshop or areawith inadequate ventilation. Special precautions are needed when welding inconfined spaces where there is the risk of the build up of inert shieldinggases.
Carbon monoxide, formed as a result of incomplete combustion of fuelgases, can also cause asphyxiation by replacing the oxygen in the blood.Establishing safe levels of fume in the workplaceThe COSHH Regulations* require that exposure is controlled belowspecific limits. The limits, known as occupational exposure limits, aredetailed in EH 40 which is revised periodically. The majority of limits listedare for single substances. Only a few relate to substances which are complexmixtures; welding fume is one of these. It has an occupational exposure limitbut account must also be taken of the exposure limits of the individualconstituents.
So, in considering what would be safe exposure levels towelding fume, not only should exposure be controlled to within the weldingfume limit but also the individual components must be controlled to withintheir own limits. The assessment of exposure to fume from welding processesis covered in EH 54.Substances may have a maximum exposure limit (MEL) or anoccupation exposure standard (OES).A MEL is the maximum concentration of an airborne substance towhich people may be exposed under any circumstances.
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