Silver Steel – Welding?

[Martin CargillParticipant @martincargill50290]

 

Not quite a model engineering problem but…

A friend of mine has a small tipper truck and he needs to renew the pivots for the tipping bed, because of wear in the pivot assembly. He has reamed out the holes in the frame, these have now gone up from 25mm to 26mm (because of the wear).   He is now looking for 26mm material to make new pins and has found some 26mm silver steel. I have looked at the properties of this material and have concluded that it should be OK for this job.  However he needs to weld lugs onto the end of the pins (to make the retainers). How will silver steel cope with welding?

 

Martin

[BazyleParticipant @bazyle]

Silver steel is a strong high carbon steel but its particular feature is that it is supplied in a conveniently fairly hard state suitable for lots of things without the complication of heat treatment.  If it gets hot it loses all that and becomes soft until it is re-tempered.
So you need to be able to keep the part that is going to get wear cool while the welding is done or the whole lot will need new heat treatment.

[renardiere7Participant @renardiere7]

EN19T is the generally recommended material for excavator pins. Already in the hardened/tempered state so no post machining heat. treatment required and can be welded I believe.

[duncan webster 1Participant @duncanwebster1]

Welding silver steel will probably end in tears. The heat affected zone will be very brittle.

This link tells you about the weldability of EN 19, similar problems. Does it have to be welded  ?

https://www.mig-welding.co.uk/engineering-steels.htm

[FulmenParticipant @fulmen]

Welding of heat treatable steels is possible with some care. You will need to preheat to at least 250C and cool slowly, then reharden. Something like EN19 or EN24 would be better suited for the job (not as hard, but a lot tougher), but they will also require preheating and heat treatment after welding.

[David George 1Participant @davidgeorge1]

I would use some EN19 T or EN24T larger diamiter and turn the shank to suit the new holes and with a collar with hole drilled through on the other end and a heavy spring clip to hold it in situ. So in effect you would have a shaft with two collars on to stop it sliding out and it will be stronger than an original and no welding to harm the steel strength.

David

[Bazyle]

On Bazyle Said:

Silver steel is a strong high carbon steel but its particular feature is that it is supplied in a conveniently fairly hard state suitable for lots of things without the complication of heat treatment.  If it gets hot it loses all that and becomes soft until it is re-tempered.
So you need to be able to keep the part that is going to get wear cool while the welding is done or the whole lot will need new heat treatment.

I was always under the impression that Silver steel was supplied in the annealed state so no risk of loosing any hardness as it won’t come hardened.

[noel shelleyParticipant @noelshelley55608]

Don’t use silver steel ! I doubt you need to weld to the pins, drill a cross hole at each end, a roll pin in one end and a spilt pin the other , if you want to stop it rotating weld a small U plate on to hold the roll pin.. Plan B drill an axial hole in both ends and Thread, then bolt and a plate washer. Or use mild steel and weld anchor plates on. Fit a grease nipple and use regularly.  Noel.

[Martin CargillParticipant @martincargill50290]

Thank you for all of your replies. I have outlined what has been said to my friend and he is still wanting to use silver steel, but he is going to go down the route of cross drilling and pinning the parts.

 

Martin

[JuddyParticipant @juddy]

I’d open the pivot hole a little more and fit bushes with the standard pin, when they wear just knock them out and replace

something like this: MB2530X Bronze Backed Steel Bush 25x28x30mm Simply Bearings Ltd

https://simplybearings.co.uk/shop/product_info.php?products_id=142958&gad_source=1&gad_campaignid=23436705313&gclid=EAIaIQobChMI1bnGz5_8kQMVpphQBh221B7TEAQYBCABEgKjSvD_BwE

 

[FulmenParticipant @fulmen]

Eliminating the welding simplifies things a lot. Haven’t seen SS delivered hard before, so unless you have a source for that you will still need heat treatment. Steel like EN19/24 is usually delivered with a tensile strength around 800-1000MPa which is plenty tough but still machinable.

 

[not done it yetParticipant @notdoneityet]

Make the pin(s) with a flat bracket on one end and a hole for a lynch pin on the other? Washers as appropriate to reduce end-float.  Flat bracket plug-welded or bolted on?

An alternative to bushing is to weld on wearing items to the current parts and use a longer pin.  That was the quick fix for old front-end loaders on the farm.

[duncan webster 1Participant @duncanwebster1]

Silver steel is for making things like cutting tools which have to be hard. In 40 years as a design engineer I’ve never seen it called up for a job like this. As others have said EN 19 or 24 would be a much better choice

[SillyOldDufferModerator @sillyoldduffer]

Though welding silver-steel is unusual, should be possible.

Silver-steel is specifically formulated to simplify heat-treatment.   Excellent at what it does:

• Supplied annealed so it can be machined easily.
• Hardened simply by heating to red-heat for a short time before plunging into oil, water, or brine.  Usually water.   Oil produces less hardening.   Brine hardens more, probably far too much.
• As hardening leaves steel brittle, it’s usual to temper it by either:
  • heating the cleaned object in a flame and quenching when the colour of the Oxide Layer indicates the desired temperature has been reached. A straw colour (≈200°C) is good for cutters – tougher with somewhat reduced brittleness and hardness.  Blue (≈300°C) toughens the metal considerably, with much reduced hardness, just what’s needed for springs.  Other colours described here.  OR
  • For best results,  soak in an oven at the desired temperature for an hour per cubic inch, and allow to cool slowly.

None of the above is critical, so even clumsy oafs like me can harden and temper silver-steel.   Other hardenable steels are fussier, requiring more skill from the operator, and maybe special equipment.  The main disadvantage of silver-steel is cost –  it’s pricey.

Problem with welding Silver-steel is that it will leave the internal state confused.  Likely still soft annealed at the cold-end becoming randomly hard/brittle/tough as the weld area is approached.  Random unreliability is not good!

Normalising should fix the problem.    Not difficult: heat the part to about 800°C throughout for a minute or two and allow to cool in air.   The result is silver-steel as it was before the maker annealed it.  Any confusion in the grain structure caused by welding should be gone.

The steel will be harder than in the annealed state and I guess fairly tough and brittle.  Might be “good enough”.  If not, harden and temper in the usual way.  Or anneal for further machining by heating to ≈750°C and cooling slowly (longer the better).

Not much call for normalising in model engineering so experience may be thin on the ground.  Any experts out there?  And I can’t think of reason for normalising silver-steel apart from returning a welded part to sanity.  And I guess silver-steel is almost never welded;  it’s not what it’s for.   So a suck it and see job.  Please report back.

Dave

[DiogenesParticipant @diogenes]

But that doesn’t alter the fact that it IS NOT a suitable material for the proposed purpose.

Who fancies a motorcycle wheel spindle made out of it?

[Diogenes]

On Diogenes Said:

…. Who fancies a motorcycle wheel spindle made out of it?

A use of silver steel that is specifically warned against in “The Vintage Motorcyclist’s Workshop” by Radco.

I’d definitely push for one of the alternative steels mentioned above, or just hope that nothing else gets damaged when the silver steel fails.

Rob

[JasonBModerator @jasonb]

I’m not sure why the suggestions for any fancy steel, this is a listing for a spare tipper hinge and brackets guess what the pin is made from?

The Guy who started Thompsons used to live down the road from me now they have several factories, next time you are driving behind a tipper look and see if it is one of theirs, name on the mud flaps. Oh don’t get too close in case that hinge pin fails.😋

[Howard LewisParticipant @howardlewis46836]

Since the problem is wear, why not drill and tap so that a grease gun can be use to lubricate the pin and the bush, to reduce wear? Grease exuding from the assembly should act act as a seal against moisture and debris ingress. An occasional top up should keep out the dirt and water.

Howard

[noel shelleyParticipant @noelshelley55608]

Bear in mind where the pins are – at the rear where all the grit and muck will be ! Thin walled bronze faced bushes will last no time at all, even IF you grease them, only daily lubing will keep grit and water out and that often does NOT happen. Preventing rotation of the pin in one part largely stops wear in that part, hence lock/anchor plates. Wear usually takes place in one direction so reaming will give an off centre hole – this is an agricultural application do NOT try to be TO precise.  I ran a skip truck for 20 years !  Noel.

[Nigel McBurney 1Participant @nigelmcburney1]

Do not weld silver steel,it will break under load, A skilled welder once advised me,that for the average self taught welder dont weld steel with an en no higher than 8 ,in the case of the truck pin why not use en 8  bar 1 inch diameter which is 25.4 mm dia ,  0.6 clearance will make fitting easier and make a few spare pins and replace pins when worn,lot cheaper and safer. Just consider a broken pin causing an accident .Many years ago I made the pivot pin for a stationary engine trolley, when pushing the trolley on the path path past the house the 5/8 dia pin broke at the point where it was welded to the angle iron axle and the out of control trolley just missed the french doors . Have learned over 50 years of making stationary engine trolleys that en8 welds ok ,does not bend easily provided sensible proportions are used and dont quench the welds.

[duncan webster 1Participant @duncanwebster1]

Even EN 8 should be treated with caution. Small sections OK, but larger should be preheated, and as Nigel said, don’t quench. The reason is that the thermal inertia of the large section is sufficient to cool the zone around the weld sufficiently quickly for it to be hard/brittle

This link has more detail

https://kimetals.co.uk/blog/en8-steel-properties-and-characteristics

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