【正文】 過程時 Snug適宜 Snug: Fastener and joint mating surfaces are drawn into alignment 緊固件及連接點表層要對齊 kdPT ?扭矩控制擰緊過程 擰緊方法 扭矩上限 扭矩下限 Snug Torque (Threshold) 適宜的扭矩 (閾值 )。177。177。177。使用非常精確的扳手不能緩解再負荷式的散射，然而對負荷分散會產(chǎn)生不利影響。 25%再負荷精確度 177。 15%再負荷精確度 177。 During the Angle Tightening Portion There is no Scatter in Preload Due to Friction, Only the Scatter in Applied Angle Turned在角度緊縮部分，沒有因摩擦而產(chǎn)生負荷的散射，只有應(yīng)用角度旋轉(zhuǎn)時的散射。 A low snug torque should be used whenever possible. When a high snug torque is used, the effect of constant preload v. angle is 。 A low snug torque will also reduce the effects of torque scatter before the angle is counted. 角度計算之前，較低的適宜扭矩將會減少扭矩分散。 屈服點控制 Torque and Angle Are Monitored During Tightening緊縮時扭矩和角度是相輔相成的。 the Yield Point Identified When the Gradient Falls to a Fraction of the Maximum當(dāng)梯度下降達到最大值的一部分時，最大梯度值會被記錄，緊縮點也會被確定 。 8% 擰緊方法 屈服點控制 50% of Peak Gradient 50%的峰值梯度 Torque Gradient 扭矩梯度 Bolt Yield Point 螺栓屈服點 Torque Torque (Clamp Load)夾負荷 Angle, q 屈服點控制 Reduced Variation in Preload After Tightening:緊縮之后減少預(yù)負荷中的變形 Preload Scatter is More Dependent on Strength Variation Than Friction Variation 比起摩擦， 預(yù)分散更依賴于強度變化 Bolt Strength is More Controllable Than Friction 螺栓強度比起摩擦力可控性更強。 8% 177。 25% 177。 CAUSE FOR LOOSENING OF BOLTS 螺栓松動分類及原因 I n i t i a l l o o s e n i n g 原始松動 U n e v e n c o n t a c t s u r f a c e b e c o m e s f l a tS u b s i d e n c e l o o s e n i n g 沉降松動 P l a s t i c d e f o r m a t i o n o f b e a r i n g s u r f a c eM i c r o f r i c t i o n l o o s e n i n g 摩擦松動 F r i c t i o n b y l a t e r a l d i s p l a c e m e n t o f c o n t a c t s u r f a c e L o o s e n i n g b y p e r m a n e n t d e f o r m a t i o n o f s e a l i n gm a t e r i a l 密封材料永久變形引起的松動S e t t i n g o f t h e g a s k e t 墊圈的設(shè)置L o o s e n i n g b y o v e r t i g h t e n i n g 擰緊過度引起松動 P r o g r e s s o f p l a s t i c d e f o r m a t i o n o f b o l tL o o s e n i n g b y h e a t 加熱引起V a r i a t i o n o f i n t e r n a l s t r e s s o v e r r e c r i s t a l l i z a t i o nt e m p e r a t u r e , d i f f e r e n t t h e r m a l e x p a n s i o n o f j o i n tm e m b e r sL o o s e n i n g b y a x i a l s q u a r e e x t e r n a l f o r c eL o o s e n i n g b y a x i a l 轉(zhuǎn)向工具L o o s e n i n g b y h o r i z o n t a l a x i a l i m p a c t e x t e r n a l f o r c eBolt Looseningwith boltturning使用工具R e l a t i v e d i s p l a c e m e n t o f b e a r i n g s u r f a c e a n dt h r e a d e d p a r t 軸承表面與螺紋部分的相對位移L o o s e n i n g b y v e r t i c a l a x i a lI m p a c t b y c o l l i s i o n , l o s s a n d l o w e r i n g o fc o m p r e s s i v e f o r c e o f t h r e a d e d p a r t a n d b e a r i n gs u r f a c e b y s h o c k w a v eBolt Loosening withoutboltturning不用工具擰緊錯誤 CHARACTERISTICS DIAGRAM OF DEFECTIVE JOINT缺陷連接特征圖 ? Fa i l ure t o pr oject req uir ed t i gh t e nin g f orce 設(shè)計擰緊需求力度的錯誤 ? I ns uff i ci en t str e n gth of j oint 連接強度不夠 ? I ns uff i ci en t al l o w a ble v ari ati on w i dt h of t i gh t en i ng f or ce ? I ns t ructi o n f ai l ure of t i g hteni ng op er ati on ? I ns uff i ci en t c ou nterm ea su re f or l oo se n i n g ? N o av ai l ab l e t i g hteni ng t oo l s 無合適擰緊工具 ? N o av ai l ab l e t i g hteni ng i ns p ecti o n 無可行的擰緊檢測方法 ? E x c e s s iv e v a ria tion w idth of to rque c oeffic ie nt ? Change of c ondit ions on threa ded fric tion par t ? M a c hining fa il ur e of bolts ? Ins uf fici e nt s trengt h of bolts ? Dime nsi on e r r or of bolts ? S quar e ne s s fa il ure of be a ring s urfac e ? W rong proc e dur e of tight e ning oper a tion ? W rong t ool ha ndling b y oper a to r ? Fett ing tight e ning b y ope ra to r ? Ins truction fai lure to oper a to r ? Change of w ork ing c ondit ions of tight e ning to ols