Organic Sae 4140

SAE
4140

AISI or SAE 4140 grade is a
low-alloy steel containing chromium and molybdenum as strengthening
agents.

AISI/SAE 4140 grade is a
versatile alloy with good atmospheric corrosion resistance and
reasonable strength up to around 600 F (315 C.) It shows good
overall combinations of strength, toughness, wear resistance and
fatigue strength.

This alloy finds many
applications as forgings for the aerospace and oil and gas
industries, along with myriad uses in the automotive, agricultural
and defense industries, Typical uses are forged gears and shafts,
spindles, fixtures, jigs and collars.

KEY
FEATURE

High
quality alloy steel

High
tensile steel

Good
wear resistance

Excellent
toughness / fatigue resistance

CHEMICAL
COMPOSITION

HARDENING

This
heat treatment results in the formation of martensite after
quenching, hence a great increase in hardness and tensile strength
together with some loss of ductility. The steel should be
austenitized at 1500 to 1550 F (815 to 845 C), the actual
temperature being a function of chemical composition within the
allowed range, section size and cooling method. Austenitizing should
ensure all micro-constituents in the steel are transformed to
austenite. Smaller sections of 4140 might be quenched in oil, heavier
sections in water

TEMPERING

Tempering
is carried out to relieve stresses from the hardening process, but
primarily to obtain the required mechanical properties. The actual
tempering temperature will be chosen to meet the required properties,
and in many cases will be a matter of trial and error. Tempering
should not be carried out between 400 790 F (200 420 C)
to avoid the danger of embrittlement