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  Welding Safety with Gas Cylinders On an oxyacetylene system there will be three types of valves,  the cylinder valve, the regulator valve, and the torch valve . There will always be a set of three valves for each system, since  the gas in the cylinders is at high pressure. A broken off valve will release extremely high pressures, which could cause the cylinder to become an extremely deadly flying missile. For this reason, never move an oxygen tank around without its valve cap screwed in place. An oxygen tank is especially dangerous for the reason that the oxygen is at a pressure of  21 MPa (3000 lb./in² = 200 atm) . Oxygen cylinders are generally filled to approximately  2200 psi . The regulator  converts the high pressure  gas  to a low pressure  stream suitable for welding. It is not recommended to directly use high-pressure gas. Pressurized cylinders must at all times be handled with great care.  Shielding gases  such as carbon...

  Bend Test Coupon Preparation First the centerline on the plate shall be marked. Then another line  1.0 inch  above the center line  and another line 1 inch below the center line. This is the section that can be used as an  alternate coupon  in the event of  corner cracks  with no evidence of slag inclusions. Next, marking of the actual  root  and face bend specimens. Using the top and bottom line, another line a minimum of  1½ inches above.   The top line shall be marked and then  1½ inches below  the bottom line. The  minimum width  of a test specimen needs to be  1½ inches  wide. After that the  Welding Inspector shall mark the weld test coupons  for a root and face bend in agreement with the welder, cutting them on a band saw. Backing Bar Removal: The  backing bar  removal can be done using a vice and using a grinder on the center of the backing bar to gouge it, about ...

  Most field welding machines are portable, that is, they are on a truck and can be moved around. The welding equipment is usually a generator driven by a gasoline-powered engine and puts a DC current that may be reversed by changing the leads. The  welding machine  must contain a gauge or some means of determining the amperage output along with some method of increasing or decreasing the amperage as desired. The leads shall be in good condition with cleaned connections at both ends. Good quality electrodes are a must. Welding manufacturers produce good quality electrodes that conform to the AWS test requirements, however, this does not ensure their good quality when delivered to the job site. The welder should discard any damaged electrodes. When using low hydrogen electrodes, he/she must furnish them from undamaged hermetically-sealed containers and have an oven for maintaining their dryness. The welder’s cleaning tools should consist of a chipping hammer and a wire bru...