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High-Speed Steel, Charge 1: Crucible-Melted Tungsten-Chrome-Molybdenum Steel (Carnegie & Gladwyn 1918)
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28. Oṣù Kẹwà 2026NO
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High-Speed Steel, Charge 1: Crucible-Melted Tungsten-Chrome-Molybdenum Steel (Carnegie & Gladwyn 1918)

High-speed steel holds its edge when it is cutting hot. In Sheffield it was made like other crucible tool steel: the best Swedish bar iron melted in small clay pots in a coke fire, with tungsten, chromium and molybdenum added to the liquid iron. This is the first of three typical charges given by Carnegie and Gladwyn: 82 lb iron, 13 lb tungsten powder, 5 lb ferro-chrome and 4 lb ferro-molybdenum for 100 lb of steel. Source: D. Carnegie and S. C. Gladwyn, Liquid Steel (1918), pp. 74-77, 106-107 and 113. Unknown: how the Swedish iron, the tungsten powder and the ferro-molybdenum are made; the melting time; and how the ingot is worked into bar. The book stops at the liquid steel, so these are linked to unknown heads. Picture: the book's Fig. 29, crucible furnaces at Samuel Osborn & Co., Sheffield.
Ògbóǹtarìgì
1 day

Ìlànà

1

Weigh charge 1

For 100 lb of steel: 82 lb best Swedish bar iron, cut up; 13 lb tungsten powder (96 to 98 % tungsten); 5 lb ferro-chrome (60 % chromium); 4 lb ferro-molybdenum (80 % molybdenum). Unknown: how the Swedish iron, tungsten powder and ferro-molybdenum are made. The book only lists them.

Àwọn ohun èlò fún ìgbésẹ̀ yìí:

Irin ọ̀pá ti SwedenIrin ọ̀pá ti Sweden82 lbs
Ìyẹ̀fun tungstenÌyẹ̀fun tungsten13 lbs
Àdàpọ̀ irin àti chromiumÀdàpọ̀ irin àti chromium5 lbs
FerromolybdenumFerromolybdenum4 lbs

Àwọn irinṣẹ́ tí a nílò:

Òǹwọ̀n ìdọ́gbaÒǹwọ̀n ìdọ́gba
2

Set two clay crucibles in the melting hole

Tool steels are melted in small crucibles, about 55 lb each, two to a hole in a Huntsman coke furnace (ours: the 100 lb charge split between the two). Stand them on fireclay stands on the fire bars, straight from the annealing furnace, and fill the hole with coke up to their tops. Use the best washed coke, as free from sulphur as possible: sulphur gets into the steel even through the lid. When the pots are white hot, throw in a little sand to fuse them onto their stands.

Àwọn irinṣẹ́ tí a nílò:

Ìléru kóńdóÌléru kóńdó
Ìkòkò Amọ̀ Tí Ń Kojú InáÌkòkò Amọ̀ Tí Ń Kojú Iná
Èédú metalurgiÈédú metalurgi
IyanrìnIyanrìn
Ẹmú Ìkòkò Ìyọ́Ẹmú Ìkòkò Ìyọ́
3

Melt the iron, then add the alloys

Charge the cut iron, put on the clay lids, fill the hole with coke and close the cover. Renew the fire as it burns through. Add the tungsten powder and ferro-alloys to the liquid iron and melt them in. Unknown: the melting time and temperature for this charge. The book says only that tool steel takes longer than ordinary steel. About 3½ tons of coke go to each ton of high-speed steel.

Àwọn irinṣẹ́ tí a nílò:

Ìléru kóńdóÌléru kóńdó
Èédú metalurgiÈédú metalurgi
Ẹmú Ìkòkò Ìyọ́Ẹmú Ìkòkò Ìyọ́
4

Pull out, skim and teem

Lift each pot out with the pulling-out tongs (arms and legs covered with wet sacking), take off the lid and skim the slag with a mop, then pour the steel into ingot moulds. Unknown: the ingot size. A clay crucible lasts about 3 heats.

Àwọn irinṣẹ́ tí a nílò:

Ẹmú Ìkòkò Ìyọ́Ẹmú Ìkòkò Ìyọ́
Àwòṣe fún ìṣù irinÀwòṣe fún ìṣù irin
Ìbọ̀wọ́ Tí Ń Fara Da OoruÌbọ̀wọ́ Tí Ń Fara Da Ooru
5

Work the ingot into round bar

Unknown: how the ingot is heated, hammered or rolled, and annealed into round bar. Carnegie and Gladwyn stop at the liquid steel, so this step is linked to an unknown head until a source gives it.

Àwọn irinṣẹ́ tí a nílò:

Ètò àlùdá àìmọ̀Ètò àlùdá àìmọ̀

Àwọn ohun-èlò

4

Àwọn irinṣẹ́ tó nílò

9

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