CStanford":32aiokvr said:
T10 is a Chinese designation for a water hardening high carbon tool steel with about 1% carbon content. The US designation of this steel is W1.
I'm not sure this is quite the place for an abstruse metallurgical argument, but in strict terms that's not quite correct. W1 has a lower silicon and manganese content. In practical terms, both W1 and T10 (and CS95) will behave in similar (but not absolutely identical) ways if quenched in water (or brine) on hardening, but the slight difference in alloying element content allows CS95/T10 to respond positively to oil quenching, which whilst it will give very slightly different results, can be an advantage for some applications (springs, for example).
(For all practical woodworking purposes, the resulting plane iron/chisel/saw will be perfectly fit for service whether made of appropriately heat-treated W1, T10, CS95 or many other alloys. There may be slight differences in performance, but all will work quite acceptably.)
Here's a quote from 'Engineering Metallurgy' Vol.1 by R.A.Higgins (fifth edition 1983, page 339)- "Silicon dissolves in ferrite thus increasing it's strength and hardness. Low alloy steels containing silicon as the principal addition are relatively inexpensive, but because silicon has a graphitising effect these steels also contain up to 1% manganese as a carbide stabiliser. Both elements combine in strenghening the ferrite and in increasing hardenability, so that silicon-manganese steels repond to oil quenching. Subsequent tempering provides a good combination of strength and impact toughness. These steels have been widely used for coil and leaf-type springs, as well as for a variety of tools such as punches and chisels where shock-resistance is necessary."
Having had to dabble in metallurgy for professional and amateur reasons, one thing that I've become aware of is the horrendous complexity of steel metallurgy. Very small changes in the percentage of an alloying element can make significant differences to the resulting steel, and there are about ten commonly used alloying elements in addition to carbon. One reference book we had in the drawing office listed 4000 grades of commercially-available steel, of which several hundred were 'tool steels'. The result is that there are many 'quite similar' grades that have differences just enough to suit them to particular applications, but which will answer perfectly acceptably in many others. Hence the variety of steels used over the years for making woodworking tools. There are quite a number of other grades that would make good woodworking tools, too.
Edit to add -
T10 - Carbon 0.95%
Manganese 0.36%
Silicon 0.32%
Phosphorus 0.031%
Sulphur 0.029%
The balance - Iron.
CS95/En44 - Carbon 0.95 - 1.05%
Manganese 0.3 -0.7%
Silicon 0.35% max.
Phosphorus and Sulphur 0.05% max each
The balance - Iron.
W1 - Carbon - 1.05%
Manganese - 0.25%
Silicon - 0.2%
(Phosphorus ans Sulphur - not specified, but will be limited as the above alloys.)
The balance - Iron.
Conclusion - T10 will make a very good plane iron. So will CS95/En44 and W1, given suitable heat treatment of each.
