Search results for query: *

Thanks miningman, I think that I am fairly confident now. One problem with concrete is the (unknown) chemical composition of the aggregate. If lime products are capable of killing a flame then even the ? possibility ? of a potentially flammable component is not a serious risk. Thanks for...

Thanks ubrales, That is very positive. We are trying to figure out the best way to clean a contaminated concrete surface. The work must be done remotely so the prior testing of samples would be difficult - but not impossible. Thanks for the advice, Regards, Bob

Thanks Flame, That is very reassuring; and other sources give similar indications. I didn't pay enough attention in chemistry lessons, so I'm glad that you guys stayed awake ! Regards, Bob

Thanks jheidt2543, I understand that the large ratio of surface area/ volume is a significant factor in dust explosions, but I presume that the molecules of the particles would have to be capable of combining with oxygen to enable combustion to start. Unfortunately, my knowledge of chemistry...

Mechanical engineer requires advice with chemistry problem !! Is it possible for fine concrete powder, any size, any concentration (generated by crushing during demolition) to ignite in dry air ? Any info welcome.

Thanks nbucska, Not quite the answer we were hoping for!! sigh! but even the bad news helps us to determine the strategy that is most likely to succeed. To be honest, at this point no-one is 100% certain of composition. Thanks again, Bob

Hi Wayne, This is a list taken from a nuclear industry design specification:- Recommended Materials (with 'good' stability at ambient temperatures in air with irradiation levels of 100,000 Grays): Polyurethane, SBR Butadiene styrene, Ethylene propylene, copolymer EPDM, Polychloroprene...

Thanks again Hacksaw, I'm certainly getting value on this one. The item is inside a stainless steel sheath. We managed to reach it with a swiss file and it seemed considerably harder than normal mild steel - but there could be several other explanations for that. At the moment the sample...

Dear sreid, Thanks for the tip. The only snag is that there are two types of components; one is plain mild steel, the other (allegedly)contains boron in some (unspecified) form or other. We only have a sample of one of them and no-one is certain which !!! (sounds like a question in the...

Thanks Hacksaw, Sorry to be so long replying; I had other work for the past fortnight but the Boron problem will be back on the agenda when our sample comes back from cutting trials. The magnetic properties of the material could be an important feature of the work, so thanks for highlighting...

Dear Hacksaw, Thanks for your contribution. I've had great difficulty getting information on this one - the actual owners of the items cannot even be certain what the composition really is !!! So there is a lot of guessing going on. Every piece of information is useful and I appreciate...

Thanks again Nick, I appreciate that this is an area of fairly limited interest. The steel in question was made in the sixties for nuclear use; much has been forgotten and many records are lost. So every bit of information is useful. Regards, Bob

Dear NickE, Thanks for such a rapid response. Do you definitely KNOW that the iron structure will be unchanged ? I appreciate that Boron is a small atom, but so is Carbon. 4% sounds a helluvalot to me - but then, I'm not a metallurgist !!! Regards, Bob

Can anyone tell me if low-carbon steel with 4% boron (as used for nuclear control-rods) would still be magnetic ?

Well done unclesyd, I will try electroarc. I am also waiting for a reply from 600centre near Loughborough who claim to know all there is to know on this and similar subjects. I think you have got me started on the right road here, so thanks again, All the best, Bob

Thanks UncleSyd, The problem is essentially to cut round a tube with 10 mm wall thickness. This is a 'demolition'-type job so the quality/ width of the cut is not particularly important. Have you any idea what cutting speed might be possible and what the relationship between power and speed...

Alan, Thanks for a very prompt reply. My own experience was that these techniques were only for small, precision items - so your information is very encouraging. The items we have to cut are in a nuclear vault and the work must be done remotely, so I doubt that we can use a standard...

Is it possible to cut through 10 millimetre mild steel plate using electrical discharge/ wire erosion/ spark erosion type machines ? How much power would it take ? What cutting speed ? Who makes such a machine ? Is any university researching this field ? Any information welcome.

Thanks yet again Andy, I am involved in proposals to dispose of some rods. The only original information we had was a drawing of a grey (mild steel) rod. We knew boron came into it somewhere and there were references (of unknown reliability) to boron carbide. I am fairly confident that we...

Thanks again Andy, I will put your info together with the other stuff I've got and see if I can work-out what goes in the gaps. I'll also ask our local library to source the book; they have managed it occasionally in the past. I've been trying to get this information from site staff since...