If the bolts are not stressed sufficiently into their elastic range, any relaxation in the gasket could reduce the sealing ability of the joint. To the other extreme, if the bolts were stressed beyond their elastic range and into the plastic range of their material of construction the same issue would apply; they would lose their dynamic load on the gasket. In that case, if they did not shear, they would take a set. Any relaxation in the gasket will then result in the reduction or elimination of the joints sealing ability.
The nut should be selected to complement the bolt. The bolt material specification will steer you, either partially or completely, into the proper nut selection.
ASME A307, a material standard for bolts in the low-strength category, states that the proper grade for bolts to be used for pipe flange applications is Grade B. The standard goes further to state that when used for pipe flanges, Grade B bolts require a Heavy Hex Grade A nut under ASTM A563. In writing a pipe specification that included the A307 bolt, you would not need to specify the nut, since it is already defined in A307.
However, ASTM A193, alloy and stainless-steel bolts, goes only so far when it states that nuts shall conform to ASTM A194—there are several grades of A194 nuts to select among. This is an example of where the matching nut is not always explicitly called out in the ASTM standard. Because the ASTM standards are inconsistent in that regard, the specification writer must make sure that the nut is covered in a specification.
In summary, all four components—flanges, bolts, nuts and gaskets—have to be selected in conjunction with one another in order for the joint assembly to perform in a way that it is expected to for a given application.
選擇低強度螺栓可用於壹類600法蘭接頭與適當的gasketing將需要螺栓要扭轉超出其屈服點，或在最低限度，超出其彈性範圍，解釋這簡單，螺栓作為彈簧，當他們安裝並加載適當的。在為了使法蘭接頭，以維持壹個墊片密封，它需要動態加載。動態加載法蘭螺栓，使膨脹和收縮運動和周圍的聯合，同時保持密封。要實現這個目標，運用足夠的壓力，螺栓考慮到材料的彈性範圍內。
如果螺栓不強調，充分考慮到他們的彈性範圍內，任何放寬，在墊片可以減少密封能力的聯合。到了另壹個極端，如果螺栓被強調，超出其彈性範圍，並納入塑膠壹系列的物質建設的同時，問題將適用於他們將失去他們的動態負載對墊片。在這種情況下，如果他們不剪，他們會采取壹套。任何放松，在墊片，然後將結果在減少或消除關節的密封能力。
螺帽應選擇，以配合螺栓。螺栓材料的規格，將引導您，無論是部分或完全，到適當的螺母的選擇。
對ASME a307 ，材料標準，螺栓，在低強度類別，國家適當職螺栓可用於管道法蘭申請壹級乙標準更進壹步說明，當用於管道法蘭， B級螺栓的要求壹個沈重的Hex A級螺母下，美國ASTM a563 。在寫作的管道規格，其中包括a307螺栓，妳不會需要指定螺母，因為這是已經確定的a307 。
不過，美國ASTM a193 ，合金及不銹鋼螺栓，雲只有這樣，到目前為止，當它指出，堅果應符合美國ASTM a194 -有幾個等級， a194堅果選擇之間。這是壹個例子，那裏的配套螺帽並不總是明確要求指出，在ASTM標準。因為ASTM標準不壹致在這方面，規格，作家必須確保螺帽是涵蓋在壹個規格。
總括來說，所有四個組成部分-法蘭，螺栓，螺帽和墊圈-要選定在聯同另1 ，以便為聯合大會在執行的方式，這是預期某壹特定的應用。