The 13 Types of Flanges for Piping Explained
常见介绍13种管道法兰介绍

Which are the most common types of flanges used in piping? How do they look like? The key types of flanges are the welding neck, long welding neck, slip-on, socket weld, lap joint, threaded and blind flanges. In addition to these standard flanges, some special ones exist, called Weldoflange/Nipoflange and Elboflange, swivel flange, expander/reducer flange, and orifice flanges.

管道中最常见的法兰类型是什么？他们看起来怎么样？法兰的主要类型有焊颈法兰、长焊颈法兰、滑套法兰、承插焊法兰、搭接法兰、螺纹法兰和盲法兰。除了这些标准法兰外，还存在一些特殊法兰，称为Weldoflange/Nipo法兰和Elboflange、旋转法兰、膨胀机/减速机法兰和孔板法兰。

STANDARD TYPES OF FLANGES
法兰的标准类型

Let’s now dive in, showing the key types of flanges with pictures.
现在让我们深入研究，用图片展示法兰的关键类型。

WELDING NECK FLANGE
焊颈法兰

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A welding neck flange (“WN”)features a long tapered hub that can be welded with a pipe.
焊接颈法兰（“WN”）具有一个可与管道焊接的长锥形轮毂。

This flange type is used, normally, in high-pressure and high/low temperatures applications that require an unrestricted flow of the fluid conveyed by the piping system (the bore of the flange matches with the bore of the pipe).
这种凸棱类型通常用于需要管道系统输送的流体不受限制流动的高压和高/低温应用中（凸棱的孔径与导管的孔径匹配）。

The absence of pressure drops prevents negative effects as turbulence and erosion/corrosion of the metals in the proximity of the flanged joints.
无压强可防止法兰接头附近金属的湍流和侵蚀/腐蚀等负面影响。

The tapered hub allows a smooth distribution of the mechanical stress between the pipe and the weld neck flange and facilitates the execution of radiographic inspections to detect possible leakages and welding defects.
锥形角皮凸允许在导管和焊颈凸棱之间平滑分布机械应力，并有助于执行射线照相检查，以检测可能的泄漏和焊接缺陷。

The dimension of the flange (NPS and the pipe schedule) shall match the dimension of the connecting pipe.
凸棱的量纲（北极星序和导管一览表）应与连接导管的量纲匹配。

LONG WELDING NECK
长焊颈

Long weld neck flanges (“LWN”) are similar to weld neck flanges, with the exception that the neck (tapered hub) is extended and acts like a boring extension.
长焊颈法兰（“LWN”）与焊颈法兰类似，但颈部（锥形疣突）被延伸，并起到镗孔外延的作用。

Long weld neck flanges are generally used on vessels, columns or barrels. These flange types are available also in the heavy barrel (HB) and equal barrel (E) types.
长焊颈法兰通常用于容器、立柱或筒体。这些凸棱类型也可用于重型桶（HB）和同等桶（E）类型。

SLIP ON FLANGE
滑动法兰

A slip-on flange is connected to the pipe or the fittings by two fillet welds, one executed inside and one outside the cavity of the flange.
滑动凸棱通过两个角焊缝连接到导管或配件，一个在凸棱的空腔内，一个在空腔外。

Slip-on flanges are also defined “Hubbed Flanges” and they are easy to recognize due to their slim and compact shape.
滑动法兰也被定义为“带颈法兰”，由于其细长紧凑的形状，易于识别。

WELD NECK VS SLIP ON FLANGE
焊颈与滑动法兰

Flanged joints made with slip-on flanges are, in the long run, a bit more fragile than connections made with welding neck flanges (in similar service conditions). This seems due to the following facts:
从长远来看，使用滑套法兰制成的法兰接头比使用焊颈法兰制成的接头（在类似的使用条件下）更脆弱。这似乎是由于以下事实：

1. ·a welding neck flange features a tapered hub, absent in a socket weld flange, which distributes the mechanical stress between the pipe and the flange more evenly承插焊凸棱中没有锥形疣突，焊颈法兰具有锥形轮毂，可以更均匀地分布导管和凸棱之间的机械应力

2. ·a welding neck joint as only one welding area instead of two (socket weld flange).仅将焊颈节片作为一个焊接区域，而不是两个（承插焊凸棱）。

Another advantage of the welding neck flange is that it can be connected either to pipes and fittings, whereas socket weld flanges suit pipes only.
焊颈凸棱的另一个优点是，它可以连接到管道和配件，而承插焊接法兰仅适用于管道。

THREADED FLANGE
螺纹法兰

Threaded flanges are available in sizes up to 4 inches and multiple pressure ratings, however, they are used, mostly, small size piping in low pressure and low-temperature applications, like water and air utility services.
螺纹法兰的尺寸可达4英寸，具有多个压强额定值，但是，它们大多用于低压强和低温应用中的小尺寸管道，如水和空气公用事业服务。

Threaded flanges are also a mandatory requirement in explosive areas, such as gas stations and plants, as the execution of welded connections in such environments would be dangerous.
在爆炸性区域，如加油站和工厂，螺纹法兰也是强制性要求，因为在此类环境中进行焊接连接会很危险。

SOCKET WELD FLANGE
承插焊接法兰

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Socket weld flanges are connected to pipes using a single fillet weld executed on the outer side of the flange (different from the slip-on flange type that requires two welds).
承插焊接法兰使用在凸棱外侧执行的单个角焊缝连接到管道（不同于需要两个焊缝的滑动凸棱类型）。

According to ASME B31.1, to execute a flanged connection using a socket weld flange, the pipe shall be at first inserted in the socket of the flange until it reaches the bottom of the flange, then it should be lifted by 1.6 mm and finally welded.
根据ASME B31。1,1–二甲基哌啶氯化物，为了使用承插焊接凸棱执行法兰联结，应首先将导管插入凸棱的套筒中，直到其到达凸棱的底部，然后将其提升1,1–二甲基哌啶氯化物.6 mm并最终焊接。

This gap shall be left to allow proper positioning of the pipe inside the flange socket after the solidification of the weld.
应留有该间隙，以便在焊缝凝固后，将导管正确定位在凸棱套筒内。

Socket Weld Flanges are used for small-size and high-pressure piping that do not transfer highly corrosive fluids.
承插焊接法兰用于不输送高腐蚀性液体的小尺寸和高压管道。

This due to the fact that these flange types are subject to corrosion in the gap area between the end of the pipe and the shoulder of the socket.
这是因为这些凸棱类型在导管末端和套筒肩部之间的间隙区域客体受到腐蚀。

Their static strength of socket weld flanges is similar to slip-on flanges’, but their fatigue strength is higher due to the presence of a single, instead of double, fillet weld.
承插焊接法兰的静态强度与滑动法兰相似，但由于存在单角焊缝而非双角焊缝，其疲劳强度更高。

LAP JOINT FLANGE
搭接法兰

Lap joint flanges feature a flat face and are always used in conjunction with a stub end.
搭接节片法兰具有平面，通常与短端结合使用。

A lap joint flange slips over the pipe and seats on the back of the stub end and the two are kept together by the pressure of the bolts.
搭接节片凸棱在导管上滑动，座在短端的背面，两个法兰通过螺栓的压强保持在一起。

The use of lap joint flanges in combination with stub ends is a cost-effective solution for stainless steel or nickel alloy pipelines, as the material of the lap joint flange can be of a lower grade (generally carbon steel) than the material of the stub end (which has to match the pipe grade, as in contact with the conveyed fluid).
对于不锈钢或镍合金管道，将搭接节片法兰与短端合并使用是一种经济高效的解决方案，因为搭接节片凸棱的材料料袋比短端材料（必须与导管等级匹配，如与输送流体接触）的等级低（通常为碳）。

This arrangement, therefore, has these two advantages:
因此，这种安排有以下两个优点：

1. 1.reduces the overall cost of the pipeline’s flanged joints, as the use of higher grade materials is minimized;降低了管道法兰接头的总体成本，因为尽量减少使用更高等级的材料；

2. 2.bolting operations are simplified, as the lap joint flange can be rotated around the pipe to help with bolts alignment.螺栓连接操作得到简化，因为搭接节片凸棱料袋围绕导管旋转，以帮助螺栓对准。

BLIND FLANGE
盲法兰

Contrary to all the flange types seen above, blind flanges do not have a center hole, and are used to blind or seal a pipeline, a valve/pressure vessel and block the flow of the fluid.
与上述所有凸棱类型相反，盲法兰没有中心点孔，用于封闭或密封管道、区室/压力壳，并阻止流体流动。

Blind flanges have to withstand remarkable mechanical stress due to the system pressure and the required bolting forces.
由于系统压强和所需的螺栓力，盲法兰必须承受显著的机械应力。

Blind flanges allow easy access to the pipeline, as they can be easily unbolted to let the operator execute activities inside the terminal end of the pipe (this is also the reason why the blind flange type is used as manhole for pressure vessels, at times).
盲板法兰便于接近管道，因为它们可以很容易地解开，让操作员在导管的终端内执行活动（这也是为什么盲板凸棱类型有时用作压强容器的人孔的原因）。

It is maybe interesting to observe that, while this flanges type is easier to manufacture, they are sold at a premium average cost per kilogram compared to the other flange types.
值得注意的是，虽然这种法兰类型更容易制造，但与其他凸棱类型相比，其每公斤的平均成本更高。

SPECIAL TYPES OF FLANGES
特殊类型的法兰

NIPOFLANGE
Nipo法兰

Nipoflange
Nipo法兰

A Nipoflange is used for branch pipelines at 90 degrees and is a product manufactured by combining a welding neck flange with a forged Nipolet.

However, a Nipoflange is a solid single piece of forged steel and not two different products welded together.
然而，Nipo法兰是一块坚固的锻钢，而不是两种不同的产品焊接在一起。

To install a Nipoflange, the piping staff has to weld the Nipolet part of the device on the run pipe and bolt the flanged part on the flange of the branched pipe.
为了安装NIPO法兰，管道工作人员必须将器件的Nipolet部分焊接在去流段导管上，并将法兰部分锚杆在分支导管的凸棱上。

Nipoflanges are available in different materials, such as carbon steel ASTM A105 (high-temperature service), ASTM A350 (low-temperature carbon steel), ASTM A182 (stainless steel grades, including duplex and super duplex) and nickel alloys (Inconel, Incoloy, Hastelloy, etc).
Nipo法兰有不同的材料，如碳ASTM A105（高温服务）、ASTM A350（低温碳）、ASTM A182（不锈钢等级，包括双相和超双相）和镍合金（铬镍铁合金、铬镍铁合金、哈氏合金等）。

Nipoflanges are also manufactured in the reinforced variant, which has additional mechanical strength compared to a standard Nipoflange.
Nipo法兰也采用增强型制造，与标准Nipo法兰相比，具有额外的机械强度。

WELDOFLANGE
焊接范围

Weldoflange
焊接范围

ELBOFLANGE AND LATROFLANGE
ELBOFLANGE和LATROFLANGE

Other less common types of flange Olets is the so-called Elboflange (a combination of a flange and an Elbolet) and “Latroflange” (combination of a flange with a Latrolet). Elboflanges are used to branch a pipeline at 45 degrees.
其他不太常见的凸棱支管台类型是所谓的Elboflange（凸棱和Elbolet的合并）和“Latroflange”（凸棱和Latrolet的合并）。Elboflanges用于在45度处分支管道。

Elboflange
Elbof范围

SWIVEL FLANGE
旋转法兰

Swivel ring flanges facilitate the alignment of the bolt holes between the two mating flanges, a feature that is helpful in many circumstances, such as the installation of large diameter pipelines, subsea and offshore pipelines, pipe works in shallow waters and similar environments.Swivel flanges suit oil, gas, hydrocarbons, water, chemical and other demanding fluids in petrochemical and water management applications.
旋转环法兰有助于两个对接法兰之间锚杆孔的对准，这一功能在许多情况下都很有用，例如安装大直径管道、海底和外滨管道、浅水和类似环境中的导管工程。旋转法兰适用于石油、天然气、碳氢化合物、水、化学品和其他石油化工和水管理应用中的高要求流体。

In the case of a large diameter pipeline, for instance, the pipe is fitted, at one end, with a standard welding neck flange, and with a swivel flange at the other end: by simply rotating the swivel flange on the pipe, the operators can achieve a perfect alignment of the bolt holes in a way easier and faster way.
例如，在挤压筒的情况下，导管一端安装有标准的焊颈凸棱，另一端安装有旋转凸棱：通过简单地旋转导管上的旋转凸棱，操作员料袋可以以更简单、更快的方式实现锚杆孔的完美对准。

The major standards for swivel ring flanges are ASME/ANSI, DIN, BS, EN, ISO, etc. The most common standard for petrochemical application is the ANSI/ASME B16.5 or ASME B16.47.
旋转环法兰的主要标准有ASME/ANSI、DIN、BS、凝胶过滤层析、ISO等。石油化工敷贴最常见的标准是ANSI/ASME B16。5或ASME B16。47

Swivel flange
旋转凸棱

Swivel flanges can be manufactured in carbon steel (ASTM A105), alloy steel (ASTM A182 F1, A182 F5, A182 F9, A182 F91), and, stainless steel (ASTM A182 F304, A182 F304L, A182 F316, A182 F316L).
旋转法兰料袋采用碳（ASTM A105）、合金钢（ASTM A182 F1、A182 F5、A182 F9、A182 F91）和不锈钢（ASTM A182 F304、A182 F304L、A182 F316、A182 F316L）制造。

EXPANDING FLANGE (“EXPANDER”)
膨胀法兰（“膨胀机”）

Expander flange
膨胀机凸棱

Expanding flanges, or “expander flanges”, are used to from a specific point to another or to connect pipes to other mechanical devices such as pumps, compressors, and valves that have different inlets sizes.
膨胀法兰或“膨胀法兰”用于从一个特定点到另一个点，或将管道连接到其他机械设备，如泵、压缩机和具有不同入口尺寸的阀门。increase the bore of the pipeline

The expanding flange represented in the picture is a welding neck flange with a larger bore on the non-flanged end.
图中所示的膨胀凸棱是一个在非法兰端具有较大孔的焊颈凸棱。

Expanding flanges can be used to increase the run pipe bore (example: from 2 to 3 or maximum 4 inches).
膨胀法兰料袋用于增加去流段导管孔径（例如：从2英寸增加到3,4-二羟苯丙氨酸或最大4英寸）。only by one or maximum two sizes and not more