[MW:20923] Porosity in Al weld with Ar

Dear experts,

Please guide me regarding following query:

We are leading fabricator of Al light weight vessels utilizing GMAW-P process. However, we found extensive porosity problems in most of times during 2G and 4G positional welding only when utilizing 99.995% Ar as a shielding gas. In 3G and 1G position seam is getting clear with no indication. We are also using He+Ar as a shielding gas & level of porosity drastically decrease due very known technical reason " getting hot arc welding".

However due to some constraints for short span of time, we are not able to utilize He+Ar for all seams & have to use Ar as shielding gas.

In view if above please suggest how to effectively utilize Ar shielding gas without RT failure, particular to welding in 2G and 4G positions.

Base Metal: AA5083
Filler Wire: ER5183
Thickness: 4 mm
Process: GMAW-P
Shielding Gas: 99.995% Ar with moisture content <2 ppm.

WPS parameters
I-90-120 AMP (2G position)
V-18-19 V
Travel Speed-350-450 mm/min

Regards,
Maulik H. Thakkar
Welding Engg & Metallurgist
L&T, Hazira, Surat
09924732922

Comments

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change. Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...

Materails FAQs

Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...

The Schaeffler and Delong diagrams for predicting ferrite levels in austenitic stainless steel welds

Introduction Ferrite is important in avoiding hot cracking in during cooling from welding of austenitic stainless steels. 'Constitution diagrams' are used to predict ferrite levels from the composition by comparing the effects of austenite and ferrite stabilising elements. The Schaeffler and Delong diagrams are the original methods of predicting the phase balances in austenitic stainless steel welds. Nickel and chromium equivalents A 'nickel equivalent' is calculated for the austenite stabilising elements and a 'chromium equivalent' ferrite stabilising elements. These are used as the axes for the diagrams, which show the compositional equivalent areas where the phases austenite, ferrite, martensite (and mixtures of these) should be present. Although intended to show the phase balance of weld fillers, these diagrams can also be used to illustrate the phase balance of the 'parent' material. There are different diagrams for dif...

Materials & Welding

Search This Blog