|
|
In the midst of fabricating a stand for a Pro-Tools MB105 bender. Primary components include an 8" x 8" x 1/2" base; 2" x 2" x 1/4" x 30" HSS column; and 3" x 8" x 1/2" top plate. All steel HRS. Build will also host an Infinite 8 tube bender mounting plate from SWAG Offroad, in addition to a degree ring from Pro-Tools. Note: the base was open-root welded from 2ea 4" x 8" x 1/2" plates to create the 8" x 8" x 1/2" base.This is my first stick welding project. Decided to stick weld the entire build, 'cept for MIG work to the base gussets. Need to train more with SMAW vertical up. Ha! Using the Dynasty 200DX with Lincoln DC/AC 7018s (1/8") and MM175 with 0.030 solid wire. Test runs with the 7018s at 132A DCEP yielded uniform results. Really working hard on ties-ins. Managed to round the column corners without stopping. Ha! Tight arcs and eyes-on puddle at all times. Also, decided to stitch-in the gussets and nip the inside corners and outer corners for aesthetics. Major Questions:* Open-Root Pass with 7018. Used a 30deg double-bevel with an 1/8" root face and 3/32" gap. Ran 3ea passes and ground smooth. Without a backing plate, how do you achieve full-penetration? Concerned that too large a gap would have resulted in the base being fused to the welding table. Probably should of elevated the base off the welding table and then burned her in. A larger gap, say 1/8" would have aided full penetration. Check? Note: ran a final pass (3/32" 7018) to the base backside, to seal the open gap, and then ground her flush.* Multi-Pass with 7018. Only ran one pass cicumferentially to bond the column to the base. Considered running two passes, but decided against it because of the addition of the gussets. Are two passes the text-book/field answer, due to the 1/4" thick HSS controlling the geometry?* Gussets with MIG. Structural the gussets will resist bending. Should the weld lengths have been increased? On the horizontal? On the vertical? Was attempting to minimize heat imparted to the base plate and column, in order to reduce base cupping. A few progress photos of the build. { Need to rotate images! }. Still need to finish the top plate and interface the infinite 8 plate & degree ring. Finally, will prime/paint the stand and affix to the concrete floor via Hilti recessed anchors. Appreciate your feedback to the questions and comments on the welds. Attached ImagesLast edited by ManoKai; 08-07-2013 at 11:14 AM."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:Additional progress shots. Attached Images"Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:ManoKai, the general rule is to make the legs of a fillet weld as long as the thickness of the base metal. So if you're using 1/2" plate the fillet weld legs should be 1/2" long. The number of passes needed to do this will depend on the size of the electrode used to do the welding(regardless of process). If the two sides of the joint differ in thickness, use the thinner dimension to size the weld. The thinner base material should fail before the weld does; all other factors being equal.The single pass you welded all around the vertical column is going to be more than sufficient with those battleship plate gussets. You'll buckle the vertical column of the stand long before the column comes loose from the base plate.Welding up the back side of the v groove was a good choice if you needed 100% penetration on the weld joint. It was most likely overkill for the plate; since there's no way you're going to load that splice in tension. The gussets on one or more sides would have to collapse before you apply any load to the weld in the base plate. One free benefit of welding up the back side of the joint is it probably helped pull any distortion back out the joint from the front side weld.How much weld to apply to those gussets is something that an engineer could calculate. For a project like this were it's built by "eye", and the base metal is massively oversized for the job, what you did is just fine. I usually stop short of the end of the gusset, as they are very easy to undercut at the end of the triangle where there's no place for the heat to go. The side walls of the vertical tube will fail long before the gussets and their fillets let go. The only way I see that happening is if you back a truck into this sucker...You can get 100% penetration from a weld made with E7018; but it's tricky in the flat position because E7018 isn't a fast freeze rod. Simpler to flip the piece over and weld both sides, if it's possible. This is one reason lots of open butt joints are rooted with EXX10 electrodes. It's simpler to get 100% penetration without excessive reinforcement on the back side of the weld.Last edited by A_DAB_will_do; 08-07-2013 at 12:14 PM.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:To get a full penetration weld with 7018 simply flip it over and either gouge with gouging rod or use a grinder to make a nice groove then weld that side up
Reply:@ ADWD - thanks for the detailed response! Track'n on all points. 7018s are not fast-freeze a la EXX10/11s.@ justinT - IRT gouge rod, are you referring to CAC-A? Sounds as if a grinder would be the preferred option to "open up" the backside. CAC-A process would intro yet another source of increased heat into the groove for little gain.Last edited by ManoKai; 08-07-2013 at 04:51 PM."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi |
|
发表于 2021-8-31 22:48:41