Dowel Pin Alternative Material

[CTTEE]

Hi,
Valve component closure in A105, dowel pin material, can we use AISI 4140 type as altenative material to orginal A105 type. AISI 4140 low alloy steel high tensile-with yield strength almost double (485MPa) than A105.
Any concern due to Dissimilarity of material-AISI4140 dowel pin/ A105 closure.

If AISI 4140 is not recommended, any other good recommendation.

Thank you.

 

[EdStainless]

All of the steels will be very similar in terms of physical and chemical properties. Only the mechanical properties will differ.
While hard pins are nice for holding alignment you have to be careful that if something gives it is not an expensive part but rather a cheap pin. Don't go too hard.
I would have them tempered so they are only ~30% harder than the base material.
You could also use other low alloy steels.

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Plymouth Tube

 

[CTTEE]

EDStainless,
Thank you.
What other alternative low alloy steel for dowel pin ?

AISI 4140 dowel pin and A105 CLOSURE. Both considered Dissimilar metals ? any possibility of Galvanic corossion take place ?

 

[CTTEE]

EDStainless,
Thank you.
What other alternative low alloy steel for dowel pin ?

AISI 4140 dowel pin and A105 CLOSURE. Both considered Dissimilar metals ? any possibility of Galvanic corrosion take place ?

 

[EdStainless]

No there won't be any galvanic issues.
I would guess that any steel with 0.30-0.40% C would give the strength that you need.
Like I said though, you don't want the pins so hard that you risk damaging other parts.

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Plymouth Tube