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Mold Tech Texture -> Pre-Texturing Mold Finishes Required - Welding

Pre-Texturing Mold Finishes Required - Welding
Date:09.Apr.2006

 

B. Welding:

If the component ( cavity, core, slide, etc. ) is going to be welded before texturing, it is of the utmost importance that it be welded using the proper welding procedure and welding rod that is 100% compatible with the parent material of the piece being welded. Steel suppliers and / or tool welding specialists can advise you regarding the proper procedures for welding the particular type of steel you are working with.

Even a weld that has been done according to proper procedure may still have variations in its¡¯ chemistry and / or hardness which could become apparent during the texture process. We have developed etchants which can be used in some circumstances to minimize the negative effects of some welds in some steels on some texture patterns, however, welded areas may still stand out ( visually ) after texturing the component. Usually, these welds can be "hand repaired" after texturing to blend the welded area into the surrounding original material very successfully.

Should the component be H13, S7, Stainless or some other hardened steel, it becomes even more important that proper welding procedure, and the correct welding rod material be used. Hardened steels that are improperly welded are often very difficult or impossible to repair to a level of visual acceptability. It is much more likely, when dealing with the texturing of welded hardened steels, that the welded areas can be made more acceptable if the manufacturer¡¯s advice for welding is followed.

When you do weld, if the piece is going to be textured, be sure that the welded area is not porous, or flaky. These conditions will severely compromise the ability of any texture source to properly etch the steel, and subsequent repairs to the welded areas will be much more difficult. Porosity in a welded area usually necessitates peening, pinning, or rewelding of the area . Some pin holes or porosity, if located in tight corners or inside ribs, can be inaccessible for repair, so it is imperative that you avoid this condition by using a reputable welding source and proper procedure. It is almost assured that, if a piece is "cold welded", even the correct welding rod will be a problem during the texture process, since it will not properly assimilate into the surrounding metal for the purposes of texturing. Our experience has shown that the best welding results for texture purposes are jobs that have been put in a furnace and welded with compatible rod.

Under NO CIRCUMSTANCES should you ever use stainless steel , nickel or copper welds in P20 tooling. Although it is often simpler to weld with stainless steel rod, it is virtually impossible to etch and / or hand repair it in a way that provides visually acceptable results in most cases. Hardened steel welding rods should be reserved for those situations where the steel manufacturer recommends them for the texturing process, and should only then be used in accordance with proper procedures for welding that particular steel.

Welds in aluminum are also a situation that needs to be handled carefully, since the welds will almost always etch at a different rate than the surrounding aluminum, and will require hand repairs after the texturing is completed.

Use caution when you weld a surface that will be textured, and always try to let us know when you have welded and where the weld is. If we know in advance that a piece is welded, we can often suggest alternative etchants ( but not in every situation - it depends on the pattern being textured and the steel) , or modify our process slightly to do the best possible job on the welds. Be sure that the welds are "color matched", which means you may have to anneal them before texturing, as the color of the weld can show up as a difference in gloss on the part, even if the weld itself matches the appearance of the texture pattern.

Post texture weld repairs maybe an additional charge over and above any texturing quotation you may have received. We would usually call you once a welded area is discovered and it has been determined that the weld is in need of hand repair after texturing, in order to discuss cost and timing issues.

Please call us if you have any questions about texturing and welding, preferably BEFORE you proceed to do the welding, as we may be able to advise you regarding the best combination of weld and texture in order to save you time and money.



 

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