CHAPTER L. /
JUDGING OF AND TESTING MOLTEN f IRON.
In testing iron we have two properties, chemical and
physical, to which we might add the phenomenon of |
fusion. An experienced eye can often very fairly tell ?
what a casting will be, physically, by judging the I appearance of the metal when running or at rest in a
In many cases the ability to judge liquid metal [ will often prove of value, for while we seldom have
means for changing its character when, fluid, we can "^
often refrain from pouring work when our judgment !
asserts that a metal is radically wrong. There is ]
this much that can be said of re-melted fluid iron: It '
will rarely, if ever, deceive an expert, as can the judg- « ing of iron in the pig before being melted. We can rest assured that if it looks radically soft in a liquid
state, it will not prove hard in a solid one, and vice \
The ordinary moulder can, with a short experience, ;
tell the degree of fluidity, or whether the iron is »
" hot " or " dull/' Why he should be better able to r-.j*
do this than judge of its physical qualities When mol- f
ten, is mainly due to present practice not often afford- f
ing means to change or correct a metal that might not *
look right. The degree of the temperature before 1 intelligently nianijmluU'u.ounders have had opportunity for experience in crucible work, we will detail more pointsbe found a cheap temporary arrangement for melting from fifty to one hundred pounds of iron, Ferrochrom.