〔 TECHNICAL DATA 〕 STEEL MANUFACTURERS BRAND COMPARISON TABLE FOR PLASTIC MOLDS TABLE FOR HARDNESS OF MAJOR STEEL PRODUCTS AND CORRESPONDING TOOL
〔 TECHNICAL DATA 〕 STRENGTH OF BOLTS, SCREW PLUGS AND DOWEL PINS
■ Bolt strength 1) When a bolt takes the tensile load
■ Unwin safety factor @ based on tensile strength
STEEL MANUFACTURERS BRAND COMPARISON TABLE FOR PLASTIC MOLDS
Revised in March, 2017
Pt : Axial tensile load [N] σ b : Yield stress of bolt [N/mm 2 ] σ t : Allowable stress of bolt [N/mm 2 ] ( σ t =σ b/safety factor @ ) As : Effective cross–sectional area of bolt [mm 2 ] As = πd 2 /4 d : Effective diameter of bolt (root diameter) [mm]
Repeated load Impact load Pulsating Reversed
Hardness (HRC)
JIS equivalent
AISI equivalent
Aichi Steel Works, Ltd.
Sanyo Special Steel Co., Ltd.
Daido Steel Co., Ltd.
Nippon Koshuha Steel Co., Ltd.
Hitachi Metals, Ltd.
Static load
Classification
JFE Steel
Fujikoshi
Uddeholm BALR.
Material
KPM1 KPMAX
13 SC group 1055
JFE–MD1 JFE–MD3 JFE–MD5
PC55
Steel
3 4 5
5 6 5
8
12 15 15
Pt =σ t × As …… (1) = πd 2 σ t/4 … (2)
28 SCM group 4140
PDS3
Cast iron
10
M200 M201 M238 M303 M310 M315
Copper, soft metals
9
SCM group (revised)
PX5 PXA30
P20
PCM30
KPM30
HPM7
Standard strength: The yield stress for ductile materials The breaking stress for brittle materials
Standard strength Safety factor @
Allowable Stress =
33
S420 group
S–STAR D–STAR G–STAR
PROVA–400 PROVA–450
SUS group SUS group (free–cutting)
GHX
HPM38
STAVAX
HPM77
RoyAlloy
(Example) The correct size is required for a socket head cap screw to take a repeat load (pulsating) with P = 1960N {200kgf}. (The materials of a socket head cap screw are: SCM435, 38–43HRC, strength category of 12.9. ) Using formula (1) As = Pt/ σ t
35 SUS group S17400
QSH6
NAK101
U630
PSL
CORRAX
N700
Pre–hardened steel
SCM (revised)
36
P20
JHX
IMPAXHH
The yield stress for a strength category of 12.9 is σ b = 112 [kgf/mm 2 ] The allowable stress σ t = σ b/safety factor (safety factor of 5 from the above table) = 112/5 = 22.4 [kgf/mm 2 ]
SUS group
EDRO400 M303HH
SKD61 (revised)
H13
DH2F
KAP90F
FDAC
= 1960/22.4 = 8.9 [mm 2 ]
P21
PCM40S
NAK80
KAP88
HPM–PRO
M461
40
P21 (free–cutting) P21 (rust–proof)
PCM40
NAK55
KAP65
HPM1
M261
■ The bolt fatigue strength (For screws, the fatigue strength is 2 million times)
∴ The bolt with a larger effective area can be obtained from the table on the right and a 14.2 [mm 2 ] M5 would be selected.
CENA1 CENA–V HPM–MAGIC
NIMAX
Strength category
Effective cross– sectional area As mm 2
Nominal size of thread
12.9 10.9 Fatigue strength ＊ Allowable load Fatigue strength ＊ Allowable load N/mm 2 {kgf/mm 2 } N {kgf} N/mm 2 {kgf/mm 2 } N {kgf}
RIGOR SLEIPNER CALDIE CALMAX
Although, if we take into consideration the fatigue strength, we will select M6 with allowable load of 2087N {213kgf} from strength category 12.9 in the table.
QCM8 SPMR8 (Powder) QPD5 SPC5 (Powder)
K105 K110 K340
SKD11 (revised)
HPM31 ZCD–M
60
D2
AUD11
PD613
NOGA
Quench–and– temper steel
440C PROVA–500 (Powder) PROVA–400 PROVA–450
M340, M390 N685, N690 N695
SUS group 440C
M 4 8.78 128{13.1} M 5 14.2 111{11.3} M 6 20.1 104{10.6} M 8 36.6 87{ 8.9}
1117{ 114} 1568{ 160} 2087{ 213} 3195{ 326} 4204{ 429} 5537{ 565} 6880{ 702} 8928{ 911}
89{ 9.1} 76{ 7.8} 73{ 7.4} 85{ 8.7} 72{ 7.3} 64{ 6.5} 59{ 6} 56{ 5.7}
774{ 79} 1088{ 111} 1460{ 149} 3116{ 318} 4145{ 423} 5370{ 548} 6762{ 690} 8771{ 895}
57
S44004
SUS440C SUS440C SUS440C
ELMAX
2) For stripper bolts which receive the impact load, the size is decided by the fatigue strength. (Likewise for a load of 1960 {200kgf}, the material of stripper bolt would be SCM435, 33–38HRC, with a strength category of 10.9.) In the table to the right, the allowable load of strength category 10.9 for over 1960N {200kgf} is as M8 at 3116N {318 [kgf]}. Therefore, the MSB10 would be selected, with a shaft diameter of 10mm having M8 thread section. Please use dowel pins also to take the shearing load. ■ Screw plug strength Allowable load P is required for screw plug MSW30 to receive an impact load. (Material of MSW30: S45C, the tensile strength σ b of 34–43HRC is 637N {65kgf/mm 2 }.) When the root diameter section of the MSW
S–STAR D–STAR G–STAR
HPM38 HPM38S HPM77
STAVAX POLMAX MIRRAX
SUS group 420 Maraging steel
S420 group
M310 M333 V720 V721
52
GHX
QM300
MAS1C
KMS
YAG
EXEO–M21
M10 58
73{ 7.4}
50 or more
Aging–treated steel
M12 84.3 66{ 6.7}
Others
CORRAX
M14 115 M16 157 M20 245 M24 353
60{ 6.1} 57{ 5.8}
Non–magnetic steel
40
NMS1
HPM75
Demo: Special Steel Association of Japan ＊ CENA1 is an updated steel for HPM50.
51{ 5.2} 12485{ 1274} 46{ 4.7} 16258{ 1659}
50{ 5.1} 12250{ 1250}
46{ 4.7} 16258{ 1659} Fatigue strength ＊ is an edited excerpt taken from "The estimated values of the endurance limit for small screws, bolts, and meter screws for nuts" (Yamamoto).
Materials
Machined materials
Nonferrous metal
Untreated material
Thermal refined
Quenched and tempered
Parts materials
(AI–alloi) SS400 (SS41)
(Be–Cu)
DC53 (Carbide)
M
For press die
SCM435
SKD11
SKD11 SUJ2 SKH51
(AI)
HPM2T
S45C S50C
Root diameter d 1
S45C
SKS3
DC53
Processing method
Required tools
Equipment
Tools
Shear area A = root diameter d 1 × π × L (root diameter d 1 ≒ M–P) A = (M–P) πL = (30–1.5) π×12 = 1074 [mm 2 ] Yield stress ≒ 0.9 × tensile strength σ b = 0.9 × 637 = 573 [N/mm 2 ] Shear stress ≒ 0.8 × yield stress = 459 [N/mm 2 ] Allowable shear stress τ t = shear stress/safety factor 12 = 459/12 = 38 [N/mm 2 {3.9 [kgf/mm 2 ]}
is ruptured due to shearing strain, the allowable load P = τ t × A = 38 × 1074 = 40812 [N] {4164 [kgf]} When the tap is made of soft material, an allowable shear is required from the root diameter of the female screw.
(Electroforming–outside)
(Electroforming–inside)
HPM7 NAK55 PX5 HPM1 NAK80
ORVAR SUPREME (Ageing treatment) MAS1C YAG HPM38 S–STAR SKD61
For plastic mold
SKD61 STAVAX RIGOR
Cu BsBM2
HPM38
CENA1
S–STAR
FDAC DH2F
STAVAX
STAVAX RIGOR
Tools materials
HRC 10
20
30
40
50
60
70
General purpose milling cutter
Drills Reamers End mills Cutting tools Drills Taps Reamers Cutting tools Drills Reamers Taps Cutting tools
Boring on flanks and bottom
SKH– Wn–Co
Drills Reamers
High speed steel carbide
P
NC milling cutter Machining center Drilling machine Drill press Boring machine Jig borer
SKH– Wn–Co
High speed steel carbide
Taps
Cutting
Boring
■ Dowel pin strength The correct size for a dowel pin is required for it to hold repeated shear load (pulsating) of 7840N {800kgf}. (Material of the dowel pin is SUJ2, hardness 58HRC–.) P = A ×τ = πD 2 τ /4 D = (4P)/(π τ ) = (4 × 7840)/(3.14 × 188) ≒ 7.3 ∴ A size of D8 or more is selected for a MS dowel pin. Also, the tools and stock, etc. can be reduced if the size of the dowel pin is consistently large. The applicable yield stress of SUJ2 σ b = 1176 [N/mm 2 ] {120 [kgf/mm 2 ]} Allowable shear strength τ=σ b × 0.8/safety factor @ = 1176 × 0.8/5 = 188[N/mm 2 ]{19.2[kgf/mm 2 ]}
SKH– Wn–Co CBN D
High speed steel carbide Boron Diamond
End mills Cutting tools
Inside and outside machining of cylinders
General purpose lathe NC lathe Turning center
(Carbide)
(Nonferrous metal)
White fused alumina Brown fused alumina Pink fused alumina Green silicon carbide Black silicon carbide Electrodeposited boron Electrodeposited diamond Electrolytic copper, Brass Copper tungsten, Silver tungsten
WA A PA GC C CBN D
Surface grinder Cylindrical grinder Jig grinder Profile grinder Forming grinder
Do not use it so that the screw part is loaded.
Grinding
Grindstone
Grindstone
(Nonferrous metal)
(Nonferrous metal)
(Carbide)
Electrode master
Cu–
Electrode master
E D M
Electric discharge machining
–W
The information here is just an example of how to determine strength. In actual practice, it is necessary to consider various conditions, including pitch precision between holes, the perpendicularity of the hole, surface roughness, circularity, plate material, parallelism, whether it is tempered or not, the precision of the injection molding machine, production quantity, and tool wear. Therefore these strength calculation values should only be used as a guide. (These are not guaranteed figures.)
Cu–Zn W
Brass Tungsten
W E D M
Wire
Wire
1227
1228
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