chapter 14-design considerations for welding,design considerations for welding a part from resistance spot welding (rsw), three processes are most commonly used for welding metal stampings and fabrications: gas metal arc welding (gmaw) or mig; gas tungsten arc welding (gtaw) or tig; and gas welding. although a high initial investment is necessary, laser welding is being more widely employed by.12 laboratory sample preparation,the process ruptures some of the cavities, and exposes the water to evaporation. more com-monly, the grinding process results in an increase in moisture content due to an increase in surface area available for absorption of atmospheric water. both of these conditions will affect the analysis of.
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and operations of shaper-planer, drilling, milling & grinding. 4 welding: introduction, classification of welding processes. gas-welding, types of flames and theirapplications. electric-arc welding.resistance welding. soldering & brazing processes and their uses. 3 unit-iv misc. topics quality: introduction, basic concept about quality of a product. 1
between these surface treatment processes as applied to stainless steels. 2.1 descaling descaling is the removal of a thick visible oxide scale from the surface. this oxide is usually dark grey. this process is done routinely in the manufacturing steel mill before the steel is delivered. mill descaling is usually a two-stage process, one to
grinding with a 40-60 grit disc should always be followed by fine grinding using, for example, a higher grip mop or belt to obtain a surface finish corresponding to grit 180 or better. if surface requirements are very exacting, polishing may be necessary. • do not overheat the surface. apply less pressure when grinding in order to avoid creating further
color, spacing, and quantity of sparks produced by grinding. it is a fast and convenient method of sorting mixed steels with known spark characteristics. this test is best conducted by holding the steel stationary and touching a high-speed portable grinder to the steel with sufficient pressure to throw a spark stream about 12 inches long.
welding-procedures are as simple or as complex as the welding process itself. in particular special precautions are spelled out. additional operations required like pre-heating, slow cooling if needed (by what means) or stress relieving after welding (the maximum time interval from end of welding may be prescribed) are detailed with complete description of means and parameters to be used.
some of the processes that can cause material to smear include machining, honing, lapping, sanding, scraping, grit blasting, tumble de burring, and preening operations. when high pressure is used, some cleaning operations, such as vapor and steam cleaning, can
deburring by grinding. the method of removing burrs by vibration, sandblasting and roller, and is widely used by enterprises. the problem with deburring by grinding is that sometimes the removal is not very clean and may require subsequent manual processing or other means of deburring. this method is suitable for bulk small products.
welding procedure specification (wps) may be generated by an authorized person (i. e. cwi) and then submitted to the ncdot materials & testsunit (steel section) at 770a park centre drive in kernersville, nc 27284 (phone: 336-993-2300) for approval in the event that the
grinding on either the periphery or side of the wheel. tapered tapered wheels, type number 4, take tapered safety flanges to keep pieces from flying if the wheel is broken while snagging. straight cup the straight cup wheel, type number 6, is used primarily for surface grinding, but can also be used for offhand grinding of flat surfaces.
contaminated, it should be removed before flat preparation. to recondition an electrode that has minimal contamination, either new or cut off, place the electrode at an exact 90° angle to the side of the grinding wheel. cutting electrodes to length: a contaminated electrode produces an erratic arc and a contaminated weld. the best way to ensure that
adjacent to the weld and any differences in the weld filler metal. for purposes of discussion, in welding there are three zones of principal concern: 1) the solidified weld metal, composed of either base metal or base metal and filler metal; 2) the heat-affected zone (haz) in which the base metal is heated to high
applying the weld deposits cleanliness — remove rust, dirt, grease, oil and other contaminants from the surfaces to be welded. surface preparation — badly cracked, deformed or work hardened surfaces should be removed by grinding, machining or carbon-arc gouging. deposit thickness —
length of a fillet weld shall be at least four times the nominal size, or the effective size of the weld shall be considered not to exceed 25% of its effective length. 2.4.3 effective area. the effective area shall be the ef-fective weld length multiplied by the effective throat. stress in a fillet weld
welding stainless steel is one of the primary reasons for passivating. the metal surface is altered and free iron is released from the alloy. the chrome to iron ratio is also lowered in the heat affected zone of the weld. the free iron on the metal surface can initiate
many different energy sources can be used for welding including gas flames, electric arcs, electric resistance, lasers, electron beams, friction, molten metal baths and ultrasound. welding includes joining methods as diverse as fusion welding, forge welding, friction welding, braze welding, brazing, soldering and explosion welding.
manual welder. most hand welding 'fig torches require a 7.0' long electrode be cut in half to fit the manual welding torch. this can be accomplished best with the diamond cutting mechanism described in this booklet. manual & mechanized plasma arc welding the plasma arc welding process requires a very precisely shaped, tungsten electrode.
7. grinding • use both hands to maintain hold of the grinder. • allow grinder to reach full rpm before grinding. • position yourself to avoid overbalancing. • when grinding avoid placing excessive pressure on abrasive wheels. • do not grind objects on sides of grinding wheels.
when it comes to technique, grinding down a weld is pretty straightforward: move the disc (again, angled 5 to 10 degrees from horizontal) forward and backward. that’s grinding 101. but the way you apply that can be at least one root cause for trouble.
the best approach is to actively clean and passivate only the part of the surface that was actually affected by the welding process. this in all cases includes the actual weld and the heat-affected zone (areas where discoloration and other post-weld imperfections usually appear).
sigma methodology—a better way to improve work process by eliminating the defects rate in the final product. the dmaic methodology has five phases define, measure, analysis, improvement and control. define phase goal: in this phase, define the purpose of project, scope and process background for both internal and external customers. there are
nowadays welding is the most common method of shop fabrication of steel structures. in addition to being simple tofabricate, welded connection considerably reduce the size of the joint and the additional fixtures and plates. however, there is still a demand for structural members to be bolted arising from a requirement to avoid welding
once located, use the edge of the wheel to grind directly on the spot weld location. this will grind the outer panel until the spot weld has been ground off or ground enough to pop the two panels apart with a seam buster. once all spot welds have been ground, you
pasco ran a very good, top notch program during that period, the best pipe welding training in wa from my experience in numerous vocational locations. by 99205 date 10-25-2013 18:35 not to hijack this but i was at hanford for refueling #15 or was it
this leaflet is for people who use compressed gases for welding, hot cutting and similar processes. it describes the hazards associated with portable oxy/fuel gas equipment and the precautions for avoiding injury and damage to property. introduction oxy/fuel gas equipment has many uses - welding, cutting, heating, straightening, and descaling.