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Basically, no matter what the screw fasteners are, they have the specified mechanical and physical properties. So what is the mechanical and physical properties of the thread cutting screws for plastic?
mechanical and physical properties of thread cutting screws for plastic
| No. | Mechanical and physical properties | Performance level | |||||||||||
| 4.6 | 4.8 | 5.6 | 5.8 | 6.8 | 8.8 | 9.8 | 10.9 | 12.9/12.9 | |||||
| d≤16mm | d＞16mm | ||||||||||||
| 1 | tensile strength Rm/MPa | Nominal | 400 | 500 | 600 | 800 | 900 | 1000 | 1200 | ||||
| min | 400 | 420 | 500 | 520 | 600 | 800 | 830 | 900 | 1040 | 1220 | |||
| 2 | Yield Strength ReL/MPa | Nominal | 240 | – | 300 | – | – | – | – | – | – | – | |
| min | 240 | – | 300 | – | – | – | – | – | – | – | |||
| 3 | Specify a non-proportional extension of 0.2% stress RP0.2/MPa | Nominal | – | – | – | – | – | 640 | 640 | 720 | 900 | 1080 | |
| min | – | – | – | – | – | 640 | 640 | 720 | 900 | 1100 | |||
| 4 | The specification of the fastener is not proportional to the stress of 0.004 8d Rpf/MPa | Nominal | – | 320 | – | 400 | 480 | – | – | – | – | – | |
| min | – | 340 | – | 420 | 480 | – | – | – | – | – | |||
| 5 | Guaranteed stress Sp/MPa | Nominal | 225 | 310 | 280 | 380 | 440 | 580 | 600 | 650 | 830 | 970 | |
| Guaranteed stress ratio | Sp,nominal/ReL,min or Sp,nominal/Rp0.2,min or Sp,nominal/Rpf,min | 0.94 | 0.91 | 0.93 | 0.90 | 0.92 | 0.91 | 0.91 | 0.90 | 0.88 | 0.88 | ||
| 6 | Post-break elongation of machined test pieces A/% | min | 22 | – | 20 | – | – | 12 | 12 | 10 | 9 | 8 | |
| 7 | Sectional shrinkage rate of machined test pieces Z/% | min | – | 52 | 48 | 44 | |||||||
| 8 | The elongation of the fastener Af | min | – | 0.24 | – | 0.22 | 0.20 | – | |||||
| reference | 0.37 | – | 0.33 | – | – | 0.2 | 0.2 | – | 0.13 | – | |||
| 9 | Head firm performance | Do not break or crack | |||||||||||
| 10 | Vickers hardness/HV，F≥98N | min | 120 | 130 | 155 | 160 | 190 | 250 | 255 | 290 | 320 | 385 | |
| max | 220 | 250 | 320 | 335 | 360 | 380 | 435 | ||||||
| 11 | Brinell hardness/HBW，F=30D^2 | min | 114 | 124 | 147 | 152 | 181 | 245 | 250 | 286 | 316 | 380 | |
| max | 209 | 238 | 316 | 331 | 355 | 375 | 429 | ||||||
| 12 | Rockwell hardness/HRB | min | 67 | 71 | 79 | 82 | 89 | – | |||||
| max | 95 | 99.5 | – | ||||||||||
| Rockwell hardness/HRC | min | – | 22 | 23 | 28 | 32 | 39 | ||||||
| max | – | 32 | 34 | 37 | 39 | 44 | |||||||
| 13 | Surface hardness/HV0.3 | max | – | When surface hardness and core hardness are measured using HV0.3, the surface hardness of the fastener should not be 30 HV units higher than the core hardness. | |||||||||
| Surface hardness should not exceed 390HV | Surface hardness should not exceed435HV | ||||||||||||
| 14 | Non-decarburized layer thread height E/mm | min | – | 1/2 | 2/3 | 3/4 | |||||||
| Total decarburized layer depth of full thread G/mm | max | – | 0.015 | ||||||||||
| 15 | Reduced hardness after tempering/HV | max | – | 20 | |||||||||
| 16 | Destruction torque MR/Nm | min | According to the provisions of GB/T 3098.13 | ||||||||||
| 17 | Absorb energy Kv/J | min | – | 27 | – | 27 | The value is still under investigation | ||||||
| 18 | Surface defects | GB/T 5579.1 (by agreement between the supplier and the buyer, GB/T 5779.3 can be used instead of GB/T 5579.1) | GB/T 5779.3 | ||||||||||
Note: Even though the thread cutting screws for plastic material properties as specified in the table, some types of screw fasteners also reduce the load carrying capacity due to size.
If you want to customized thread cutting screws for plastic, please send an email: annie.li@szsst88.com
12 月-24-2018
kalyn
+86 13143444311
sst@szsst88.com
