Mirraloy TG&P and Kromite #3 |
SAE 4000 Series |
ELECTRIC FURNACE MELT
• smaller more refined chemistry
• more control of heat lot |
OPEN HEARTH FURNACE
• large heats - less refinement
• little control |
CLEAN STEEL TECHNOLOGY
• manufacturing process to eliminate
impurities in steel and improve fatigue
resistance
|
NOT REQUIRED |
VACUUM DEGASSING
• removes impurities in the steel to refine the
chemistry |
NOT REQUIRED |
UNIQUE CHEMISTRY
• low phosphorus, low sulfur, nickel
enhanced
• cleaner chemistry and improved strength |
STANDARD CHEMISTRY
• commercial practice follows minimum
standards |
HEAT TREATED
• thermal process is verified against strict
guidelines |
HEAT TREATED
• lacks depth and uniformity compared to
Kromite #3 and Mirraloy TG&P |
PHYSICAL PROPERTIES
• typical tensile strength 156K
• typical yield strength 123K
• typical hardness Rockwell "C" 30/32 |
PHYSICAL PROPERTIES
• typically 20% less strength than Kromite #3
and Mirraloy TG&P
• more susceptible to fatigue failure |
MACHINE STRAIGHTENED
• one half of the industry standard; 1/8" in any 5 feet |
MACHINED STRAIGHTENED
• 1/4" in any 5 feet |
STRESS RELIEVED
• thermal treatment process to reduce the
chances of "walking" or movement during
machining |
NOT REQUIRED |
FATIGUE RESISTANCE
• excellent toughness
• toughness resists fatigue failure |
FATIGUE RESISTANCE
• lower degree of toughness - subject to
fatigue failure, the number one cause of
shaft failure in heavy industry |
MACHINABILITY
• fine uniform grain promotes ease of
machining |
MACHINABILITY
• not consistent, hard and soft spots |
MECHANICAL TESTING
• Tensile, yield, elongation, reduction of area,
and jominy are checked every 10,000 lbs,
resulting in better control over physicals |
MECHANICAL TESTING
• commercially done at 50,000 lbs increments
• less control of physical properties
Designed to provide optimum performance.
SAE establishes safe minimum standards, |
| Designed to provide optimum performance. |
SAE establishes safe minimum standards,
not intended to provide optimum
performance. |
