Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS 4
- Thread starter LP2111
- Start date
See previous (ancient) thread covering this topic.
Converting energy to motion for more than half a century
Converting energy to motion for more than half a century
- Thread starter
- #3
I THINK I AM NOT ABLE TO EXPLAIN MY QUESTION. FOR EXAMPLE TAKE SA-193 MATERIAL. NOW LINE NO. 28 & 31 HAVE SAME MATERIAL LISTED BUT HAVING DIFFERENT ALLOWABLE STRESS VALUE. WHY?
WHAT IS THE `t' SHOWN IN LAST COLUMN? IF I HAVE TO CHOOSE BETWEEN THEM.. THEN WHAT CRITERIA SHALL BE FOLLOWED?
WHAT IS THE `t' SHOWN IN LAST COLUMN? IF I HAVE TO CHOOSE BETWEEN THEM.. THEN WHAT CRITERIA SHALL BE FOLLOWED?
-
1
- #4
- Thread starter
- #5
Christine74
Mechanical
While we're here, can anyone here explain why the allowable stress of some bolting materials drops as the diameter increases? Does the manufacturing process result in the outer portion of the bolt having a higher tensile strength than the inner portion?
-Christine
-Christine
-
2
- #7
EdStainless
Materials
C74, Often yes.
When you roll threads the cold work diminishes with depth.
The result is that with smaller diameters you get significant cold work while with larger ones a greater portion of the interior is not cold worked.
You also see a similar result (though from a different cause) with heat treated fasteners.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
When you roll threads the cold work diminishes with depth.
The result is that with smaller diameters you get significant cold work while with larger ones a greater portion of the interior is not cold worked.
You also see a similar result (though from a different cause) with heat treated fasteners.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
Christine74
Mechanical
Makes sense, thanks for explaining that EdStainless.
-Christine
-Christine
-
1
- #9
Christine 74,
The steels tensile and yield strength, thus the allowable stresses, drops when diameter increases due to fabrication process. When the thickness increases the material cooling slows and the grain structure is larger. If the material is thin, the cooling of the material during fabrication is quicker and the grain structure is smaller. Also, when the material is cold formed, the fabrication process increases the yield stress and the allowable strenght.
The steels tensile and yield strength, thus the allowable stresses, drops when diameter increases due to fabrication process. When the thickness increases the material cooling slows and the grain structure is larger. If the material is thin, the cooling of the material during fabrication is quicker and the grain structure is smaller. Also, when the material is cold formed, the fabrication process increases the yield stress and the allowable strenght.
- Status
Similar threads
- Locked
- Locked
- Question
