Saturday, Nov 23, 2013 at 12:46
Michael, that comment about "imported recycled steel" is ill-informed and unwarranted, and shows that you know little about steel and steel qualities.
1. China is the largest producer of finished steel in the world (700M tonnes annually). China has been a net exporter of steel since 2006.
2. China supplies steel to every developed nation in the world, including America.
China produce nearly 90% of its steel from iron ore, using mostly West Australian iron ore.
The reason China uses iron ore, is that China uses coking-coal-fired blast furnaces - the traditional steel-making method - because China does not have enough spare electricity generation ability, to be able to install the more modern electric arc furnaces, as America has done.
America now uses electric arc furnaces almost exclusively, because they can handle scrap better, are faster, and can produce small batches of precise-specification steel to order in vastly quicker times than blast furnaces.
The American steel industry now runs almost completely on scrap steel and electric arc furnaces. They use very little iron ore, because their ore is low grade taconite and requires costly processing.
They used up nearly all their high grade hematite during WW2, producing armaments and war equipment.
3. Steel quality is not reduced by using scrap steel as feed!! Scrap steel actually IMPROVES finished steel quality.
A percentage of scrap is fed into nearly every blast-furnace load to improve the final steel quality.
Electric-arc furnaces run exclusively on scrap steel.
Scrap steel is a KNOWN quality, because it has been previously refined and undesirable steel contaminants (such as phosphorus, sulphur, ilmenite, etc) have been REMOVED in the previous refining.
Every time steel is re-refined, its quality improves FURTHER.
Caterpillar used to use up to 30% scrap steel in every blast-furnace load, and did so since the days of Caterpillars predecessor, Holt. Caterpillar now use around 90% scrap steel. No-one ever says Caterpillar steel is rubbish.
4. No manufacturer in Australia, utilising Chinese MILD STEEL, has ever issued a statement about overall Chinese mild steel quality, being sub-standard.
5. A towbar tongue is made from MILD STEEL - not low alloy or high strength steel - which is used for axle steel.
Mild steel is the most common and widely-used form of steel. It's a low carbon steel, has virtually no heat-treatability - and it's used because it is easy to work with, and is strong enough for all general-purpose requirements.
Mild steel has LOW TENSILE STRENGTH. It's easily bent. Towbars and towbar tongues do not require the use of high-tensile steel.
6. Australian Design Rules (ADR) 62/00 and 62/01 cover the strength requirements, and testing requirements for towbars and towbar tongues.
http://www.transport.wa.gov.au/mediaFiles/licensing/lbu_vs_ci_116.pdf
A towbar has to be able to withstand 0.5 times the towbars capacity in vertical tension and compression, and transverse thrust, without deformation.
It has to be able to withstand 1.5 time the towbars capacity in longitudinal tension and compression without deformation.
7. A Daihatsu Charade, weighing just over a tonne, running into the back of a stationary truck weighing 3.5 tonnes, at 48kmh, generates an impact force of 181 kN (40,690lbs or 18,456kgs).
http://www.underridenetwork.org/SafetyArticles/EstimatingForcesDuringCollision.aspx
Even with a much lower impact speed, impact forces of even a small car on a stationary vehicle, are in seriously larger numbers than even a
well-designed and
well-constructed towbar and tongue can cope with, without serious deformation.
I hope this sets the record straight.
Cheers, Ron.
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