PS Magazine - TB 43-PS-572
PS, The Preventative Maintenance Monthly
ISSUE 572
JULY 2000
PS 572
57
PS 572
56
JUL 00
GRADE
BOLT & SCREW
PROOF LOAD
TENSILE
MARKING
SPECIFICATION
MATERIAL
SIZE (in)
(psi)
*
STRENGTH
(min. psi)
SAE-Grade 1
Low carbon steel
1
/
4
– 1
1
/
2
33,000
60,000
ASTM-A 307
1
/
4
– 4
—
60,000
SAE-Grade 2
Low carbon steel
1
/
4
–
3
/
4
55,000
74,000
over
3
/
4
– 1
1
/
2
33,000
60,000
SAE-Grade 5
Medium carbon steel,
1
/
4
– 1
85,000
120,000
quenched and tempered
over
1 – 1
1
/
2
74,000
105,000
ASTM-A 449
1
/
4
– 1
85,000
120,000
over
1 – 1
1
/
2
74,000
105,000
over
1
1
/
2
– 3
55,000
90,000
SAE-Grade 5.1
Medium carbon steel,
No. 6 –
3
/
8
85,000
120,000
quenched and tempered
w/assembled lock washer
SAE-Grade 5.2
Low carbon Martensite
1
/
4
– 1
85,000
120,000
steel, quenched and tempered
ASTM-A325
Medium carbon steel,
1
/
2
– 1
85,000
120,000
Type 1
quenched and tempered
1
1
/
8
– 1
1
/
2
74,000
105,000
ASTM-A325
Low carbon Martensite
1
/
2
– 1
85,000
120,000
Type 2
steel, quenched and tempered
ASTM-A325
Atmospheric corrosion resisting
1
/
2
– 1
85,000
120,000
Type 3
steel, quenched and tempered
1
1
/
8
– 1
1
/
2
74,000
105,000
ASTM-A 354
Alloy steel, quenched
1
/
4
– 2
1
/
2
80,000
105,000
Grade BB
and tempered
2
3
/
4
– 4
75,000
100,000
ASTM-A 354
Alloy steel, quenched
1
/
4
– 2
1
/
2
105,000
125,000
Grade BC
and tempered
2
3
/
4 –
4
95,000
115,000
SAE-Grade 7
Medium carbon alloy steel,
1
/
4
– 1
1
/
2
105,000
133,000
quenched and tempered, roll
threaded after heat treatment
SAE-Grade 8
Medium carbon alloy steel,
1
/
4
– 1
1
/
2
120,000
150,000
quenched and tempered
ASTM-A 354
Alloy steel, quenched
Grade BD
and tempered
SAE-Grade 8.2
Low carbon Martensite steel,
1
/
4
– 1
120,000
150,000
quenched and tempered
ASTM-A 490
Alloy steel, quenched
1
/
2
– 1
1
/
2
120,000
150,000 min
and tempered
170,000 max
Society of Automotive Engineers (SAE) and American
Society for Testing Materials (ASTM) grade marking chart
*
Proof Load is the measure of load that can be applied without causing permanent set.
NO MARK
Bolts Torque to You
To get the best from any bolt, you’ve got to use the right torque. The torque
called out in the TM isn’t somebody’s best guess, it’s the value built into the bolt.
The extra leverage you can get from
a wrench is fantastic. By turning and
turning, you can stretch a bolt com-
pletely out of shape, snap off the head,
strip threads, crack the nut, destroy
washers—not to mention damaging
what the bolt holds together.
What’s a Bolt?
In terms of mechanical advantage,
a bolt is an inclined plane. With the
added advantage of a lever—like a
wrench—a bolt can generate tremen-
dous pressure.
A bolt does its job by stretching, just
like a spring or rubber band. Here’s
how:
The tension generated by the bolt
when it’s tightened keeps the nut on
and the connection together. The same
thing happens when you screw a ma-
chine bolt into matching threads.
There are tough, strong bolts, light-
duty bolts and all sorts of bolts in be-
tween. Make sure you’re using the right
one for the job at hand.
Next time you find an empty bolt
hole, resist the temptation to fill it with
the first right-size bolt you find.
Despite their simple appearance,
bolts are really precision instruments.
Their job is as critical as any other in
the operation of a piece of equipment.
When you use a substitute, you put
your equipment and your buddies in
danger. That substitute bolt can snap at
any time.
...hand-tightened
...wrench-tightened
This is how it looks when it’s.
..
Hardware . . .
YOU CAN TELL
A LOT ABOUT A BOLT FROM
ITS MARKINGS!
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