(4) Torque Strength
Torque Wrench (0~150 kgf) (150~750 kgf) 購買(150 ~300 kgf) ASME B18.6.3 / FIP1000 / SAE J78, J81, J1237, J933 / ISO 898-7, ISO 2702 / DIN 7500-1 / IFI-113
2. TORSIONAL STRENGTH TEST扭力強度試驗
FIP 1000 Applicable To: All Tapping Screws. 適用範圍：所有種類的自攻螺絲
Test Purpose: To detect parts having low strength which might twist off during driving or seating. 測試目的：為檢查零件是否因為扭力不足而在組裝或旋緊時扭斷.
Specification: See charts that follow. 如下圖示
Apparatus required: 測試裝置
A. Appropriate Split Collet. 適當的夾具 B. Collet Holder. 夾具座
C. Screw Testing Fixture. 螺絲測試座
D. Torque Wrench; accurate with +/-2%. 準確度在?2%以內的扭力扳手
1
Sample Size(Minimum Recommended): 4 pieces per lot; lot size not to exceed 250,000 抽樣數(建議最少)：每批4支,每批批量不超過250M PCS.
Procedure: 測試程序
A. Place the split collet into the collet holder and screw the fastener into the collet such that a minimum of 2 full threads are in the collet and a minimum of 2 threads are above the collet.
將螺絲置入測試夾具中再將夾具放入夾具座, 螺絲至少應有兩個完全牙在夾具中, 兩牙在夾具上方. B. Place the collet holder in the screw testing fixture and clamp into place. 將夾具座固定在螺絲測試座上
C. Apply torque with a torque wrench until the part twists off. 扭轉扳手直到螺絲扭斷 D. Record failure value and compare to the required specification. 記錄破壞值且與規範值比較
Failure: Part twists in two at less than specified minimum. 失效：螺絲扭斷值小於規範值
Possible Failure Causes: 失效可能因素
A. Core Hardness too low. 心部硬度太低
B. Case Hardness too low. 表面硬度太低
C. Case Hardness too shallow. 有效滲碳層不足 D. Minor diameter too small. 最小徑(牙底徑)太小
ASME B18.6.3 – 2013
4.11.3 Torsional Strength Test. Screws shall be securely clamped by suitable means, such that the clamped portion threads are not damaged and that at least two full threads project above the clamping device, and that at least two full threads exclusive of point, flutes, or end slot, are held within the clamping device. (A blind hole may be used in place of a threaded clamping device, provided the hole depths is such as to insure that breakage will occur beyond the point or the full length of the flutes or end slot). By means of a suitably calibrated torque measuring device,
torque shall be applied to the screw until failure occurs. The torque required to cause failure shall no less than the minimum value given in Table 50 for the type and size of screw being tested. A typical fixture for conducting torsional strength tests on tapping screws is depicted in Fig. 4. 扭力強度測試：螺絲應以適當的方式安全的夾於一相配合的分離盲孔或其他裝置中以防止所夾緊的螺紋不致損毀，並且露出至少2全牙於夾具上至少2全牙(不包括尾端、割尾、或凹槽)握於夾具之中。(盲孔可以取代螺紋夾具，其孔深應能保証螺絲不會在尾端、割尾全長或尖尾位置斷裂)以一校正過且適當的扭力量測設備，測試直到斷裂為止，當斷裂時的扭力應不可小於表50之最小值。典
2
型的扭力強度測試設備請參考圖4 。
圖4 - 扭力強度測試參考圖
表50 － 自攻螺絲之扭力強度要求
最小扭力強度, lb-in. 螺絲規格 Type A 4 9 12 18 24 30 39 48 83 125 … 152 196 … 250 492 Type Type C , D , F, G , T AB ,B ,BF ,粗牙 細牙 BP ,BT 4 9 13 18 24 30 39 56 88 … 142 … … 290 … … 5 9 13 18 23 …… 42 56 93 … 140 … … 306 … … 3
Type TRS 粗牙 6 10 14 22 24 … 48 65 93 … 156 … … 330 … … 細牙 … … … … … … … 74 … … … … … … … … # 2 # 3 # 4 # 5 # 6 # 7 # 8 # 10 # 12 # 14 1/4 # 16 # 18 5/16 # 20 # 24 6 10 15 20 27 …… 47 74 108 … 179 … … 370 … …