There are mainly two kinds of pipe flange standards for important pipe connection at home and abroad, namely European system (by din

标准表示）和美国系统（由美国ASMEB 16.5，B16.47表示）。 标准具有代表性）。 同一系统中/地区的管道法兰标准基本上相互兼容（连接尺寸和密封表面尺寸）。 不能将两个不同的系统一起使用。

Standard) and US system (represented by asmeb 16.5, b16.47). The standard is representative). The pipe flange standards of the same system are basically compatible with each other (connection size and sealing surface dimension). You cannot use two different systems together.

（1）GB50316的相关规定

(1) Relevant provisions of GB 50316

1。 紧固件用于管道：包括六角头螺栓，双头螺栓，六角头螺母和垫圈等。

1。  Nuts, hexagon bolts, etc. for fastening pipes.

2。 从当前标准中选择标准紧固件，然后选择指定特殊用途的材料

2。  Select standard fasteners from current national standards, and then select materials for specific applications

3。 用于法兰连接的紧固件材料应符合现行的法兰标准要求，并与法兰垫片兼容。

3。  The fastener materials used for flange connection shall meet the requirements of current national flange standards and be compatible with flange gasket.

4。 用于法兰连接的紧固件螺纹的螺距不应大于3mm，并且直径为M30或更大的紧固件可以是细螺纹。

4。  The screw pitch of fasteners used for flange connection shall not be greater than 3 mm, and fasteners with diameter of M30 or larger can be fine threads.

5。 碳钢紧固件应符合当前标准

5。  Carbon steel fasteners shall meet current national standards

6中规定的工作温度。 在严重的循环应力条件下螺栓或双头螺栓，样品由合金钢制成。

6. Under severe cyclic stress conditions, the sample is made of alloy steel.

（2）“设备通用原则”的有关规定

(2) Relevant provisions of "general principles of equipment"

1。 法兰紧固件应确保垫片满足初始密封条件，并在整个操作过程中保持垫片密封。

1。  Flange fasteners shall ensure that the gasket meets the initial sealing conditions and maintains gasket sealing throughout the operation.

2。 在高温条件下，应使用PN≤2.0MPa的六角形头螺栓或全螺纹螺栓或等长双头螺栓。

2。  Under high temperature condition, hexagon head bolt or full thread bolt or equal length stud bolt with PN ≤ 2.0MPa shall be used.

3。 屈服强度不超过235MPa，低强度紧固件仅适用于PN≤2.0MPa非金属垫片的法兰连接，不应在严酷的循环场合使用，碳钢低强度紧固件]的工作温度范围 是-20℃?200℃。

3。  The yield strength shall not exceed 235mpa. Low strength fasteners are only suitable for flange connection with PN ≤ 2.0MPa non-metallic gasket, and shall not be used in severe cycling situations. The working temperature range of carbon steel low-strength fasteners is - 20 ℃? 200 ℃.

4。 当非软垫圈法兰连接使用变形和硬化的奥氏体不锈钢紧固件时，应检查紧固件的承载力，是否满足连接要求，并且使用温度不超过500℃。

4。  When deformed and hardened austenitic stainless steel fasteners are used in non gasket flange connection, the bearing capacity of the fasteners shall be checked to see if they meet the connection requirements, and the service temperature shall not exceed 500 ℃.

5。 它应满足紧固件对管道法兰（SH3404）的要求或相关标准。

5。  It shall meet the requirements of fasteners for pipe flange (sh3404) or relevant standards.

（3）选择用于法兰连接的螺栓和螺母

(3) Select bolts and nuts for flange connection

螺栓根据其形状螺栓分为单头而双头螺栓，单头螺栓仅在螺钉的一端加工螺纹，另一端是连接到螺钉本体的螺钉头。 法兰的单头螺栓通常使用六角头螺栓。 两端螺栓的两端均加工有螺纹，并呈圆柱形。 当拧紧力较大时，单头螺栓容易在螺钉和螺钉头之间的连接处断裂，因此不能在中压和高压法兰上使用。 双头螺栓不仅可用于中压和高压法兰，而且还易于从两侧拧紧。

According to its shape, the bolt is divided into single head bolt and stud bolt. The single head bolt only processes thread at one end of the screw, and the other end is the screw head connected to the screw body. Hexagon head bolts are usually used for single head bolts of flanges. Both ends of the bolts at both ends are machined with threads and are cylindrical. When the tightening force is large, the single head bolt is easy to break at the joint between the screw and the screw head, so it can not be used on medium pressure and high pressure flange. The stud bolts can not only be used for medium and high pressure flanges, but also can be easily tightened from both sides.

法兰螺母通常为六边形，分为单倒角和双倒角两种类型。 单个倒角六角形螺母与连接的零件接触的表面是平坦的，仅在另一侧倒角； 双斜切六边形螺母的两边都斜切了。 因此，与连接器的接触面积是单倒角六边形螺母的接触面较大，而双倒角六边形螺母的接触面较小。

Flange nuts are usually hexagonal and can be divided into single chamfering and double chamfering. The contact surface of a single chamfered hexagon nut with the connected parts is flat and chamfered on the other side only; both sides of the double bevel hexagon nut are chamfered. Therefore, the contact area with the connector is that the contact surface of single chamfered hexagon nut is larger than that of double chamfered hexagon nut.

螺栓根据制造方法分为粗制螺栓，半精制螺栓和精制螺栓。 除螺纹部分外的粗糙的螺栓，其余部分的外表面未精加工，是坯料的粗糙形状，相对较粗糙。 螺栓主要由普通碳钢制成，其张力不高。 半精制和精制螺栓需要进行处理，有些需要进行热处理。 它们主要用于制造碳素钢或合金钢，因此它们的张力大且耐热性高。

According to the manufacturing method, bolts are divided into rough bolts, semi refined bolts and refined bolts. The rough bolt except for the threaded part, the outer surface of the rest part is not finished, which is the rough shape of the blank, relatively rough. The bolt is mainly made of ordinary carbon steel and its tension is not high. Semi refined and refined bolts need to be treated, some need heat treatment. They are mainly used to make high quality carbon or alloy steel, so they have high tension and high heat resistance.