2017年10月18日星期三

TIG Weld - Filler Wire & Without Filler Wire

After four samples and many many communications. Finally our client accept our sample, for below fasteners with three bolts welded on the plate




It seems simple but the client has high quality on welding portion, especially the welding angle, depth, the roundness of welding seams, even the welding bellow shapes. we were all solved. 
And after resolved all above questions there new problem happened, it was the welding current, we are difference. our welding current is 50A-150A, but the client insist their welding current is 200A-230A. that's really a big difference. and the client starts to worried about our welding strength. 
But our engineers insist that based on our welding method, the materials would be damaged in 200A current. Everything was deadlocked and stopped.
In order to improve our welding strength no problem, we made a test, use one of bolts to hang up a 2 tons titanium ingot. and success. it proved that this parts with three bolts can hang up 6 tons at least. then the result is our welding strength is no problem.
We also test the samples that client provided, all no problem.
But why the big difference welding current but all the welding are OK?
Accidentally, the client took a welding process pictures to me, and we found that it seems no weld wire (fillet wire) during welding. then, all the questions were answered.  
The client weld method is self- fusible, but our method was use filler wire. self-fusible weld asked high current and high temperature, but filler wire weld only 50-150 is enough. 
At the beginning, we were all think that we used the same weld method and ignored it. and after this experiences, we should recognize that we cannot ignore every small details during communication. and should also more on the other side of the position to consider the issue.

Maybe I should prepare an article about two different welding method for TIG Welding. 
Finally, showed the video of that interesting test of welding strength.

2017年10月9日星期一

TITANIUM ASTM Grade 29 (R56404)

Grade 29 -- Titanium alloy (6% aluminum, 4% vanadium with extra low interstitial elements, ELI) plus 0.08% to 0.14% ruthenium.



Grade 29 titanium is a titanium alloy formulated for primary forming into wrought products. R56404 is the UNS number for this material. Additionally, the ASTM designation is Titanium Grade 29.

It has a moderately high heat capacity among wrought titanium. In addition, it has a moderately low melting temperature and a moderately high embodied energy.


Titanium  Grade 29 Mechanical Properties


Grade 29 Elastic (Young's, Tensile) Modulus

Grade 29 Elongation at Break

Grade 29 Fatigue Strength

Grade 29 Poisson's Ratio

Grade 29 Reduction in Area

Grade 29 Shear Modulus

Grade 29 Shear Strength

Grade 29 Tensile Strength: Ultimate (UTS)

Grade 29 Tensile Strength: Yield (Proof)


Titanium Grade 29 Thermal Properties 


Grade 29 Melting Onset (Solidus)

Grade 29 Specific Heat Capacity

Grade 29 Thermal Conductivity

Grade 29 Thermal Expansion

Ti-6AL-4V alloy is the most widely used titanium alloy of the alloy of the alpha-lus-beta class, and is also the most common of all titanium alloys. This modification incorporates extra low interstitials (ELI) and also has a ruthenium addition to enhance the corosion properties. The wrought material is used in applications where moderate strength, good strength to weight, and favorable corrosion properties are required. The alloy is available as wire, sheet, bar, plate, forgings, billet and rings.


Based on this material, the product form including:

  1. Sheet, Streip, and Plate (ASTM B265);  
  2. Bar and Billet, Annealed (ASTM B348);  
  3. Seamless and Welded Fittings (ASTM B363);  
  4. Forgings (ASTM B381);  
  5. Seamless Pipe (ASTM B861);  
  6. Welded Pipe (ASTM B862);  
  7. Wire (ASTM B863);  
  8. Weld Wire (AWS A5.16 ERTi-29).


Grade 29 Chemistry Composition

N           C           H           Fe           O           Al             V            Ru                Ti
0.03     0.08      0.015      0.25        0.13    5.5-6.75   3.5-4.5    0.08-0.14     Balance




More detailed information can reference ASTM standards.