metallurgical expertise | Sodel International Sale https://www.sodelinternationalsale.com Sodel International Sale Fri, 15 May 2020 14:53:08 +0000 en-US hourly 1 How to differentiate between different types of material ? https://www.sodelinternationalsale.com/2016/04/01/how-to-differentiate-between-different-types-of-material/ Fri, 01 Apr 2016 20:32:24 +0000 http://www.sodelinternationalsale.com/?p=2242 As a doctor who wants to make the right diagnosis, the welder must also, analyze the situation before determining the right medication that will allow him to reach the desired result. To make a proper analysis you need to know the base material; it is imperative to have knowledge of what the material consists of, that you want to weld. A mistake in the material identification could be very costly. In the following article we will inform you of some metals that are often confused such as aluminum, zinc and magnesium.

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]]> As a doctor who wants to make the right diagnosis, the welder must also, analyze the situation before determining the right medication that will allow him to reach the desired result. To make a proper analysis you need to know the base material; it is imperative to have knowledge of what the material consists of, that you want to weld. A mistake in the material identification could be very costly. In the following article we will inform you of some metals that are often confused such as aluminum, zinc and magnesium.

With the eye, it is almost impossible to differentiate between these three steels, because it is their properties that identify what type of metal it is.

Here is a chart showing their differences :

Element Symbole Point of fusion Density at 27⁰C (g/cm3)
Aluminum Al 660⁰C 2,70
Magnesium Mg 649⁰C 1,74
Zinc Zn 420⁰C 7,14
Iron Fe 1540⁰C 7,86

We can see that for a same metal volume the weight of the zinc is more than two time higher than aluminum or magnesium and is similar to the one of iron or steel. The point of fusion of the zinc is approximately 2/3 the one of aluminum and magnesium.

Now, how to concretely differentiate magnesium from aluminum. It is possible to find a quick answer to this question. You just need to make a very simple chemical reaction test. The magnesium reacts with table vinegar. You just need to put a little bit of vinegar on a corner of a well cleaned part. If the vinegar reacts with the part (it is possible to see little bubble formation on the part surface), if this is the case, we have magnesium. If there is no reaction we have an aluminum alloy.

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]]> welding method can effect the ferrite number https://www.sodelinternationalsale.com/2016/04/01/welding-method-can-effect-the-ferrite-number/ Fri, 01 Apr 2016 20:30:28 +0000 http://www.sodelinternationalsale.com/?p=2238 Last week we had a question from a customer that had to weld a 304H stainless steel part using a 308H electrode. The contract specification was requesting a ferrite number between 3 and 6 on the weld beads. They tough that they would be in line with specifications in using a 308H coated electrode with a ferrite number of 5,5 (calculated from WRC 1992 diagram). What was the final result when analyzing with the Ferritscope probe ? A ferrite between 0 and 2 FN; how could it be possible ?

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]]> welding method can effect the ferrite number

Last week we had a question from a customer that had to weld a 304H stainless steel part using a 308H electrode. The contract specification was requesting a ferrite number between 3 and 6 on the weld beads. They tough that they would be in line with specifications in using a 308H coated electrode with a ferrite number of 5,5 (calculated from WRC 1992 diagram). What was the final result when analyzing with the Ferritscope probe ? A ferrite between 0 and 2 FN; how could it be possible ?

One of the most powerful chemical elements affecting ferrite level is the dissolved nitrogen in the weld bead. For evaluating ferrite level, welding rod manufacturers consider an ideal nitrogen level of 0,06% in any stainless steel (300 series) weld metal. This is the nitrogen content you should get if you weld their rods using prescribed parameters. It is important to understand that nitrogen is not added intentionally in the coated rods. As a matter of fact, nitrogen which dissolves in the austenitic stainless steel comes from the ambient atmosphere. To obtain this low ideal nitrogen level of 0,06% in the weld metal, you have to maintain a very short arc.

In the present case, the project requested to realize 308H weld beads containing 94 to 97% of austenite and 3 to 6% of ferrite. If the customer uses a too long arc, he should obtain a dissolved nitrogen level in the weld bead over 0,06%. Nitrogen being a powerful austenitizer (a chemical element which stabilizes austenite to the detriment of ferrite), that’s why the measured ferrite number is lower than expected. In this situation you have two possible ways to obtain the requested ferrite : shorten the arc length using the same rod rated at 5,5 FN or keep a long arc using a rod rated at 8 or 9 FN. If you choose the second solution, the long arc will give you higher nitrogen content which should lowers the weld metal ferrite to the requested range. Because a higher than normal nitrogen level can have an effect on the weld bead mechanical properties, you should carefully consider this last solution.

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