EN 13480-3; allowable stress determination acc. to 5.2.2-1

[TomoB]

Hello,

I have encountered a problem when calculating the allowable stresses for bolts made of A2-70 material.
In a formula 5.2.2-1 of EN 13480-3 it is stated to use the second formula if Rm,t is available.

https://files.engineering.com/getfi...28b4-42cb-89b7-3b118ce97539&file=Formula1.png

For temperature of 20 °C the ff value is determined acc. to the second formula, becauseRmt is known for 20°C.
This leads to higher allowable stresses at higher temperatures, because Rmt is not known and the value is calculated according to the first formula.
For example, allowable stress at 35 °C is much higher than allow. at 20°.

https://files.engineering.com/getfi...ba12-4283-9485-9fa58fca06c1&file=Picture2.png

Has anyone approached this problem before and what would be the advice on how to proceed?

Thank you for your time!

Kind Regards,
Tomislav Begic

 

[XL83NL]

Is this for a standard flange? Have you looked at para 6.6.3 for that matter? That refers to EN 1515 series.

Huub
- You never get what you expect, you only get what you inspect.

 

[ione]

I'd expect the tensile stress @20 °C and @ 35 °C to be almost the same. In any case the formulas reported in EN 13480-3 refer to Rp,1.0 and not Rp,0.2.

As suggested by XL83NL, you could take a look to EN 15515-4, which as standard reference for X5CrNi18-10 (EN 1.4301EN) addresses to EN 10269, where you can find mechanical properties vs temperature tables.