Was it the very end of the bar? Sometimes the end bit is not much good. Something to do with the production process.

I tend to buy most of my steel by the bar length. Usually 3 metres long, this is cheaper and I like having a good stock.

As standard practise I cut the first 2"/50mm off the end and throw it in the scrap box.

Even buying whole lengths is no protection. I bought several full lengths of allegedly bright EN1A from a small local supplier approaching a decade ago and reckon there were at least three different types of steel in the bunch. Different heat treatments and conditions too. Judging by how they behaved when turning and cutting probably only 3 of 8 could be rightfully treated as close enough to EN1. First part I tried to thread was rather worse than Robins first example. Starting some way back down the bar too. The good bits threaded beautifully.

Fortunately most of that particular job was rough work. Bit about that long with a hole about that size sort of thing. But a couple of lengths were going into stock. Sorted good ones for that. Still not exactly the same tho'.

Dropping into stuck record mode we really need to stop buying steel by EN numbers and use more modern designations. 230M07 rather than EN1A for example. The EN specifications are just too sloppy to work with these days, especially as there is little control of material condition. EN3B is a good example. Nearest is probably 070M20 but if you get bright bar it could well be 080A15, which should be supplied with a test certificate to show the properties match adequately. That one doesn't matter much as folk like us will be hard pushed to notice any difference between 070M20 and 080A15 when machining.

There is a lot of overlap between steel grades. We are more concerned with condition, which generally defines how it works, than exact composition. If it waddles like a duck, quacks like a duck then it is a duck. But if, metaphorically speaking, you order duck and get bombay duck on the plate you are, I think, entitled to be a bit miffed. Which is about what happened to Robin.

It would be nice if we could find someone with plenty of experience in the modern supply chain able to give appropriate modern designations for materials that will work well for us and have consistent properties regardless of supplier.

Clive

Edited By Clive Foster on 20/01/2020 09:47:02

Edited By Clive Foster on 20/01/2020 09:47:35

Edited By Clive Foster on 20/01/2020 09:48:00

I bought some 100mm cast iron from a well-known supplier. It was for some cylinders for my loco. I started machining it, thinking, "This is funny cast iron swarf!" I cut off a small piece of the bar and put it in the vice. I hit it with a hammer. It bent through 90°. In all fairness, they quickly replaced the steel bar supplied with the correct material, but I do wonder sometimes with commercial purchasing, which involves Certificates of Conformity, how often the C of C is incorrect…

Most likely it's the bar end. Whilst Black Steel and Bright Mild Steel have exactly the same chemical composition, their physical properties are noticeably different. It's because rolling steel Bright Mild Steel involves reheating and work hardening. In the same way cutting bar steel adds an area of suspect behaviour.

Can't agree with Mick's suggestion the cause is 'inclusions of different steel types in a cheap gash melt', because it implies steel is made haphazardly in small quantities. Actually steel making is high-tech, with perhaps several hundred tons of metal heated well above melting point, chemically analysed and then purified in the furnace to meet a particular specification. Slag eroding off the furnace might cause inclusions, but unmelted ball-bearings are unlikely. It is possible for trouble to occur later when the steel is cooled and processed. Cooling too fast or too slowly will change properties, as will cutting fast and hot, rolling, or missing out stages such as Normalisation because many big customers prefer to do their own.

Another problem might be our determination in the UK to buy 'EN1A'. "Emergency Number" specifications were forced on the British Steel Industry by government because the War effort demanded consistent steel, rather than whatever Hadfield, Firth, Colvilles, Dorman, Consett, Guest and all the others happened to be pushing as their proprietary free-cutting mild-steel. Although chaps swore by certain Brands, defeating Nazi Germany required Industry to behave consistently. Standardisation did the job so well EN numbers survived: no-one went back to the pre-war buying methods.

As the Emergency Number system is long gone, I suggest 'EN1A' today isn't a consistent product. As far as I know, no-one in the world makes actual EN1A, though there are many steels like it. Therefore what you get is a similar steel, like 220M07, or 230M07, or SAE1113, or SAE1213, or Workstoff 1.0711/1.0715, or JIS SUM25 or whatever else the supply chain thinks best. Almost for sure it's made in the Far East in a modern steel plant.

I feel it's a good example of old-fashioned British engineering conservatism causing unnecessary confusion: EN1A entirely ceased to be in 1991, yet it's still what I have to ask for in my local stockist. I've had better results since telling them I want to machine the steel. Pretty sure I'd get a different mild-steel if I said it was to be welded. I'm fairly sure that today's metal 'quality' problems are more to do with people having the wrong specification rather than the metal itself being faulty. There are a tremendous number of different steels in use compared with the last century. Life isn't simple, especially machining unknown scrap or one of the less suitable alloys. I reckon the Golden Age of straightforward home engineering ended about 1970, since then Industry has moved ever further away from 'our' materials and techniques. Unlikely that anyone will make an IMLEC winner featuring stampings, ground and laser cut components, welded stainless steel, extruded & die-cast plastics, robotic assembly, a FEM analysed and computer optimised design, low carbon emissions, and half a dozen microcontrollers!

Simple answer to Robin's question, buy free-cutting steel, check how it cuts#, and avoid the ends!

Dave

# My stock box contains samples of 'EN1A' rods and strip bought at different times. Although it all machines reasonably well there are obvious differences between some samples. The differences are more noticeable with Carbide than HSS, requiring up to 20% more-or-less speed, depth-of-cut and feed-rate for best finish.

Like Chris I tend to buy small bar stock (<2" diameter) in the standard 10ft lengths. i haven't generally had a problem using bar ends on cold drawn steel bar. I have had occasional problems turning and milling material, even that sourced from the larger steel stockholders.

The tolerances on the composition of most materials are quite wide and I suspect get minimal testing. If you're making a low carbon steel are you going to be worried about chucking in some medium carbon alloy steel, like a bicycle frame? For critical applications one can buy certified materials which should be what they say on the tin and possibly come with a composition certificate. But it'll cost you.

It probably minimises, but doesn't eliminate, the problem by purchasing from trusted suppliers, but it depends upon usage. As an example the large bar of supposedly EN1A I turned recently to make a tapered former had some odd surface effects. I bought cheap from Ebay, but was fully aware that there might be some issues. However, the former will get used for making two chimneys and then be recycled in some form, so I wasn't worried about odd or poor finishes due to the material.

Andrew

EN1A is so much more understandable that 230M07.

As for C of Cs, these have to be used with a degree of scepticism. I used to work in the aircraft industry where C of Cs are mandatory but it didn't stop a Californian steelworks from falsifying the paperwork.

Brian

Only if you think you know what EN1A is! Doesn't have much currency outside the UK, for example EN1A isn't mentioned at all in my copy of Machinery's Handbook.

The later British Standard system is logical, When the code is understood, designations like 230M07 give far information about the type of steel it is describing:

000-199 are Plain Carbon Steels with some Manganese
200-240 are Free-cutting versions of 000-199
300-499 are Stainless
500-999 are Alloy steels other than stainless

Depending on the group, the first 3 digits are meaningful, 220 means 2% Sulphur

'A' means the steel has a specified chemical analysis
'H' means the steel has specified hardenability
'M' means the steel has specified mechanical properties.

The last two digits indicate the Carbon content.

So the code 230M07 gives a clear indication of the steel's composition and it's purpose – it has particular mechanical properties. In a basic workshop using only a few different basic steels, EN1A is simple and helpful because no-one has to think. But those meaningless EN numbers are unhelpful to anyone looking for steels to meet advanced requirements.

Not a good idea to have practical men using a different system to the designers and purchasers because it causes lost in translation mistakes. I think it's only tolerated in the UK…

Dave

Lets face it companies pay for C of C's because their quality controls system demands it. that's leaves suppliers with dodgy metal nowhere to sell the known / suspect stuff to except model engineers who won't set the lawyers on you when they find out it's rubbish.

I thought it probably was – but I'm still amazed Conan Doyle gets away with it…

Maybe, it might have been made in a British Furnace like this, first built in 1711 and closed after various upgrades in 1966, long after it was obsolete:

Picture Attribition Wikipedia: The photo is of a small manual producer, not very scientific, with quality depending mostly on the skill of the individuals operating it. Capable of good results, but not when the skilled operator is drunk, ill or on holiday! Or his boss insists on cutting corners. This sort of 'stirring scrap in a pot' operation may be what chaps imagine goes on in the Far East. Very unlikely!

Far more typical of modern steel-making is the British Steel plant at Scunthorpe:

Plants like this are highly mechanised, highly efficient, with most sources of human error removed. This is the sort of operation unlikely to make steel containing unmelted inclusions, or steel outside the target specification.

Sadly the Scunthorpe Steelworks was sold for £1 in 2016 and went into receivership, bankrupt, last year. Nothing wrong with quality, the problem was cost. This relatively small steelworks relying heavily on imported materials and an expensive workforce, couldn't compete with the really big boys. No profit in it.

To give an idea of scale, 1,808,000,000 tons of steel were made in the world during 2018. China made 928,300,000 tons of it, and the second largest producer was the European Union, at 168,200,000 tons. In 2018, the entire British steel output was 7,700,000 tons, or 0.43% of the world total, slightly less than Egypt. Of course quantity isn't everything, in 2020 steel made in Britain will be something special, high-quality, made in an electric furnace for very demanding applications.

China's dominance of steel isn't entirely wonderful for them because the market for steel is ferociously competitive and very vulnerable to sudden drops in demand. Large inflexible enterprises catch bad colds : about 2 million Chinese steel workers have been made redundant since 2018, which makes British job losses in the steel sector look like chicken-feed, agonizing though they were. (In the UK, about 250,000 lost jobs since 1967, or roughly 50 years). Change in the steel industry, wherever it happens to be located in the world, can occur quickly. British steel production peaked in April 1970 at nearly 2.9 Million tons, but collapsed to 0.13 Million tons in February 1980.

It's not that I believe inclusions are impossible, only that modern steel production methods make them far less likely than in the past. Can anyone post a photo of a recognisable inclusion found by them in a bit of modern metal? Slag is far more likely than ball bearings and gears!

Dave