Penetration on Pretty Welds

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Hey I'm new to this forum and have searched for an answer.  Seems like lots of the pros can diagnois welds by pics.  Question I have is when I work with my miller and use recomended settings my welds look horrible and are very thick.  When I adjust settings to make a weld that I can control better welds look great and seem to burn in great.  Question is can you have a great looking weld and it not have the proper strength.
Reply:JC Cowboy, Basically, the answer is yes. Depending on what type of welding you are doing, (stick, MIG, etc.) appearance is a plus, but it can hide serious defects. Starting out, use junk material. Lay a bead, then break it and see what it looks like. Did you get good penetration? Keep doing that until you can take your welded piece, put it into a vise and pound on it to the point where the material breaks somewhere else besides the weld.
Reply:First of all, what machine/process are you using?Second, exactly what do you mean by "proper strength"?Strength could refer to the size and design of the weldment. For example, a quarter inch fillet weld holding a bulldozer bucket to the mounting points will not have adequate strength regardless of the quality of the weld, welder, or weldor.Strength could also refer to metallurgical strength. A if the weld metal has the wrong chemical composition it will not be able to support the necessary loads regardless of the quality of the weld, welder, or weldor.But I'm going to assume by "proper strength" you meant proper fusion and penetration. Penetration is how deep the weld goes into the joint and/or base metal. Fusion is how much the sides of the weld cross section melt into the sides of the joint.Just remember, it's a lot harder to make a pretty weld thats bad then it is to make an ugly weld that's good.No doubt someone (or several people) will come along and start spouting about how GMAW (a.k.a MIG) makes it really easy to make a "pretty" weld that is not properly fused or penetrated. I think this is more of a myth than anything. That sort of thing ususally happens because a welder (the machine) is underpowered, the setting are running too cold (in sufficient amperage), and/or the weldor (the person) is not actually watching and reading the puddle. Of course all this can happen with any of the the open arc welding processes, not just GMAW.That being said, while you can tell a lot about a weld just by looking at it, the outward appearance can only give you clues as to how well the weld penetrated and fused. The only time you can definitely tell visually how much a weld penetrated is if it is an open-root joint and you can actually see the root of the weld. Other than that the only way to definitively tell how much a weld penetrated (without the use of x-rays or ultrasonics) is to cut and etch a cross section of the weld (of course this destroys the weld in the process so is only useful for testing purposes).Post pictures of the welds if you can and we'll tell you as much as we can about the welds.Visit Tensaiteki.com
Reply:Originally Posted by TensaitekiJust remember, it's a lot harder to make a pretty weld thats bad then it is to make an ugly weld that's good.
Reply:tensaiteki has given very sound sage advice here, heed his admonishments.I will add this to the mix when setting up a machine, I will select settings that if one is not careful will blow holes in the material, and adjust down from there.This applies to materials 1/4" and underFor all 110v power source GMAW machines I always start on the hottest setting.TJ
Reply:Tensaiteki is correct though the bit about gmaw is no myth. I have seen it too many times and the root of the problem is guys who don't know what they are doing concentrating on the wrong priority. They all want to make a pretty bead but forget about penetration and tie in. Looks real nice, but falls apart just sitting. The puddle and what is taking place in it as the weld is being laid is far more important than cosmetics. It had absolutely nothing to do with the machines being underpowered, unless you consider 250 amp Miller production machines to be underpowered. Concentrate on getting it right and the looks will come with practice. The settings the manufacturer gives are just a basic guide. Every machine is a little different and there are many other factors involved as well, such as ambient temperature, humidity level, length of leads, the quality of the ground, etc.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Visual inspection is used by EVERY code or specification that I have ever heard of.  It is the cheapest and most widely used of all inspection techniques.  If it can't pass visual, there's no reason to bother with xray, ultrasound, etc.With PROPER training and/or experience, you can tell a lot about a weld based on its appearance.Last edited by Engloid; 03-30-2008 at 08:23 PM.
Reply:same here jolly!!