RF, FF, RTJ Flange Face and Finish
RF、FF、RTJ法兰表面和光洁度

The flange face is the surface area that hosts the gasket. The 6 available types of flange face are flat (FF), raised (RF), ring joint (RTJ), lap joint, male and female (M&F), tongue and groove (T&G). Flanges with different faces require different gaskets and shall never be mated to prevent leakage of the joint. RF and FF flanges may have different types of “finish” (i.e. roughness on top the surface): smooth, stock and serrated.

法兰面是承载垫圈的表面区域。6 种可用的法兰面类型是 平面 (FF)、凸起 (RF)、环形接头 (RTJ)、搭接接头、公母 (M&F)、榫槽 (T&G)。不同面的法兰需要不同的垫圈，并且不得配合以防止接头泄漏。RF 和 FF 法兰可能具有不同类型的“光洁度”（即表面顶部的粗糙度）：光滑、粗制和锯齿状。

FLANGE FACE TYPES
法兰面类型

The ASME B16.5 and ASME B16.47 norms mention a few different types of flange faces:
ASME B16。5和ASME B16。47规范提到了几种不同类型的法兰面：

1. ·Flat face flange (FF)平面法兰（FF）

2. ·Raised face flange (RF)凸面法兰（RF）

3. ·Ring joint flange (RTJ)环形节片法兰（RTJ）

4. ·Lap joint flange搭接节片法兰

5. ·Male and female flange (M&F)外螺纹和内螺纹法兰（M和法[拉]）

6. ·Large and small tongue-and-groove flange (T&G)大小榫槽法兰（T和G）

Let’s take a closer look at the different types of flange faces, RF, FF, lap joint, ring joint, grooved:
让我们仔细看看不同类型的法兰面，RF、FF、搭接呼、环形呼、沟槽：

RAISED FACE FLANGE (RF)
凸面法兰（RF）

A raised face flange (RF) is easy to recognize as the gasket surface area is positioned above the bolting line of the flange.
凸面法兰（RF）很容易识别，因为垫圈表面区域位于法兰的螺栓连接线上方。

The main scope of a raised face flange design is to concentrate the pressure of the two mating flanges on a small surface and increase the strength of the seal.
凸面法兰设计的主要范围是将两个对接法兰的压强集中在一个小表面上，并增加密封的强度。

The most common flange finish for ASME B16.5 RF flanges is 125 to 250 micron Ra (3 to 6 micron Ra). The raised face is, according to ASME B16.5, the default flange face finish for manufacturers (this means that buyer shall specify in the order if another flange face is required, as flat face or ring joint).
ASME B16最常见的法兰表面处理。5 RF法兰为125至250微米Ra（3,4-二羟苯丙氨酸至6微米Ra）。根据ASME B16，凸面为。5.制造商的默认法兰面光洁度（这意味着，如果需要另一个法兰面，如平面或环形节片，买方应在订单中指定）。

Raised face flanges are the most sold type of flange, at least for petrochemical applications.
凸面法兰是最畅销的法兰类型，至少在石化应用中是这样。

FLAT FACE FLANGE (FF)
平面法兰（FF）

Flat face flanges (FF) have a contact surface having the same height as the bolting line of the flange. Full face gaskets, generally of the soft type, are used between two flat face flanges.
平面法兰（FF）的接触面高度与法兰的螺栓连接线相同。在两个平面法兰之间使用通常为软型的全表面垫片。

According to ASME B31.3, a flat face flange should never be mated with a raised face flange as the resulting flanged joint would definitely leak.
根据ASME B31。3,4-二羟苯丙氨酸，平面法兰不应与凸面法兰匹配，因为由此产生的法兰节片肯定会泄漏。

RING JOINT FLANGE (RTJ)
环形接头法兰（RTJ）

A ring joint flanges (RTJ) is used when a metal-to-metal seal between the mating flanges is required (which is a condition for high-pressure and high-temperature applications, i.e. above 700/800 C°).
当需要在对接法兰之间进行金属对金属密封时（这是高压和高温应用的条件，即高于700/800库[仑]），使用环形节片法兰（RTJ）。

A ring joint flange features a circular groove to accommodate a ring joint gasket (oval, or rectangular).
环形节片法兰具有圆形坡口，以容纳环形节片垫片（椭圆形或矩形）。

As the two ring joint flanges are bolted together and then tightened, the applied bolting force deforms the gaskets inside the flange groove creating a very tight metal-to-metal seal. To make this happen, the material of the ring joint gasket has to be softer (more ductile) than the material of the flange.
当两个环形节片法兰用螺栓连接在一起然后拧紧时，施加的螺栓力使法兰坡口内的垫圈变形，形成非常紧密的金属对金属密封。为了实现这一点，环形节片垫片的材料必须比法兰的材料更软（更具延展性）。

RTJ flanges can be sealed by RTJ gaskets of different styles (R, RX, BX) and profiles (example: octagonal/oval for the R style).
RTJ法兰料袋用不同样式（R、RX、BX）和型材（例如：R样式的八角形/椭圆形）的RTJ垫片密封。

The most common RTJ gasket is the R style with an octagonal section, as it ensures a very strong seal (the oval section is an older type). A “flat groove” design, however, accepts both RTJ gaskets having an octagonal or oval section.
最常见的RTJ垫片是带有八角分段的R型，因为它确保了非常牢固的密封（椭圆形分段是一种较旧的类型）。然而，“平坡口”设计可以接受两个具有八角形或椭圆形分段的RTJ垫片。

LAP JOINT FLANGE
搭接法兰

TONGUE AND GROOVE FLANGE (T AND G)
榫槽法兰（睾酮和G）

Two tongue and groove flanges (T&G face) perfectly fit one into the other: one flange has a raised ring, the other a groove and they can be mated easily (the tongue enters the groove and seals the joint).
两个榫和坡口法兰（睾酮和G面）完美地将一个安装在另一个中：一个法兰有一个凸起的环，另一个是坡口，它们料袋轻松匹配（榫进入坡口并密封节片）。

Tongue and groove flanges are standardized in both large and small types.
舌型和坡口法兰在大型和小型两种类型中都是标准化的。

MALE AND FEMALE FLANGE (M AND F)
内外法兰（M和法[拉]）

Similarly to tongue and groove flanges, male and female flanges (M&F face type) match one to the other as well.
与榫和坡口法兰类似，凸法兰和凹法兰（M＆法[拉]面型）也相互匹配。

One flange has an area extended beyond its face area, the male flange, the other flange has a matching depression machined on the facing surface, the female flange.
一个法兰的面积超过其表面面积，外螺纹法兰，另一个法兰的表面上加工有匹配的凹陷，内螺纹法兰。

The female face is 3/16” deep, while the male face is 1/4″ high, and both of them are smooth finished.
女性面部深3,4-二羟苯丙氨酸/16英寸，而男性面部高1,4-二氮杂环己烷/4英寸，两者都是光滑的。

The outer diameter of the female face retains the gasket.
内表面的外径保留垫圈。

FLANGE FACE FINISH
法兰表面光洁度

To ensure that a flange mates with the gasket and the companion flange perfectly, some roughness is required on the flange surface area (RF and FF flange finish only). The type of roughness on the flange face surface defines the type of “flange face finish”.
为了确保法兰与垫片和配对法兰完美配合，法兰表面需要一些粗糙度（仅RF和FF法兰表面处理）。法兰表面粗糙度的类型定义了“法兰表面光洁度”的类型。

Common types are stock, concentric serrated, spiral serrated and smooth flange finish.
常见类型有岩株、同心锯齿、螺旋锯齿和光滑法兰饰面。

Steel flanges are available with four basic face finish, however, the common objective of any type of flange face finish is to create the desired roughness on the face of a flange to ensure a strong match between the flange, the gasket, and the mating flange and thus provide a high-quality seal.
钢法兰有四种基本的表面光洁度，然而，任何类型的法兰表面光洁度的共同目标是在法兰表面形成所需的粗糙度，以确保法兰、垫片和对接法兰之间的牢固匹配，从而提供高质量的密封。

Let’s now dive into the most common flange face finish types:
现在，让我们深入了解最常见的法兰表面处理类型：

STOCK FINISH
库存整理

The stock finish is the most widespread type of finish as it suits the large majority of applications. The pressure embeds the soft face of the gasket into the flange finish and results in the formation of a good seal due to the friction existing between the contacting parts.
岩株表面处理是最广泛的表面处理类型，因为它适合大多数应用。压强将垫片的软面嵌入法兰表面，由于接触部件之间存在摩擦，从而形成良好的密封。

As the mating flanges are bolted together, gaskets get “squeezed” into the flange face surface and create a very tight seal.
当对接法兰用螺栓固定在一起时，垫圈“挤压”到法兰表面，形成非常紧密的密封。

A stock finish face is manufactured using a phonographic spiral groove featuring a 1.6mm radius round-nose tool with a depth of 0.15mm and a feed-rate of 0.8mm per revolution. The resulting “Ra” value (AARH) for the surface ranges from 125inch to 500 inch (125 m to 12.5 m).
岩株精加工面使用留声机螺旋坡口制造，其特征是1.6mm幅度圆头工具，深度为0.15mm，进给速度为每转0.8mm。表面产生的“Ra”价值观（AARH）范围为125in至500in（125m至12.5m）。

SPIRAL SERRATED
螺旋锯齿

Spiral serrated finish is a phonographic spiral groove type that differs from the stock finish as the groove is crafted by a 90 degrees tool (instead of a round nosed one) that creates a “V” geometry with a 45-degree serration angle.
螺旋锯齿面是一种唱机螺旋坡口类型，不同于岩株面，因为坡口是由90度工具（而不是圆头工具）制作的，该工具可以创建具有45度锯齿角的“可变区”几何形状。

A serrated finish, concentric or spiral, has from 30 to 55 grooves per inch and roughness between 125 to 250 inch.
锯齿表面，同心或螺旋，每英寸有30到55个凹槽，粗糙度在125到250英寸之间。

CONCENTRIC SERRATED
同心锯齿

The concentric serrated flange finish features concentric grooves instead of spirals.
同心锯齿法兰表面具有同心凹槽而非螺旋。

The grooves are crafted by the same 90-degree tool used for the spiral serrated finish, but the serrations have an even design on the face of the flange. To have concentric grooves, the tool has a feed rate of 0.039mm per revolution and a depth of 0.079mm.
凹槽由用于螺旋锯齿表面的相同90度工具制作，但锯齿在法兰表面具有均匀的设计。为了具有同心槽，工具的进给速度为每转0.039mm，深度为0.079mm。

SMOOTH FINISH OR FACE
表面光滑

Flanges with a smooth finish do not show visible tool markings at naked eye.
表面光滑的法兰肉眼看不到明显的工具标记。

This type of flange finish is used with metal-facing gaskets such as the jacketed type.
这种类型的法兰表面处理与金属表面垫片（如夹套式）一起使用。

As per the stock finish, this is achieved by having the contact surface machined with a continuous spiral groove generated by a 0.8mm radius round-nosed tool at a feed rate of 0.3mm per revolution with a depth of 0.05mm (that creates a roughness between Ra 3.2 and 6.3 micrometers, i.e. 125 – 250 microinches).
根据岩株表面光洁度，这是通过使用0.8mm幅度圆头工具以每转0.3mm的进给速度、深度为0.05mm（这会产生Ra 3.2和6.3微米之间的粗糙度，即125–250微英寸）生成的连续螺旋槽加工接触面来实现的。

COLDWATER FINISH
冷水饰面

The cold water finishes appear shiny to the naked eye and very smooth. The AARH value for these surfaces ranges between 85 inch to 100 inch. They are used with metal to metal seals (no gasket).
冷水饰面在肉眼看来闪闪发亮，非常光滑。这些表面的AARH价值观在85英寸到100英寸之间。它们与金属对金属密封件（无垫圈）一起使用。

WHAT IS AARH?
什么是AARH？

The term AARH (“arithmetic average roughness height”) refers to the flange face smoothness/roughness. The average arithmetic roughness height values are very important during the selection of flanges and gasket materials. Higher the “Ra” values depict a more rough surface, while lower values represent the smoother surface.
术语AARH（“算术平均粗糙度高度”）指法兰表面平滑度/粗糙度。在法兰和垫片材料的选择过程中，平均算术粗糙度高度值非常重要。“Ra”值越高表示曲面越粗糙，而值越低表示曲面越平滑。

Every material possesses a surface roughness and sometimes surfaces are finished deliberately to have a specific roughness (small or bigger).
每种材料都有一个表面粗糙度，有时故意对表面进行精加工，使其具有特定的粗糙度（小或大）。

The “Arithmetic Average Roughness Height” (AARH) is the common indicator to measure the roughness of a surface, and it is the average height of the irregularities on the metal surface, from the mean line as shown in the following figure.
“算术平均粗糙度高度”（AARH）是测量表面粗糙度的常用指标，是从下图所示的均值线算起的金属表面不规则的平均高度。

The symbol Y1 to Y8 represent the peak heights which are measured from the mean line.
符号Y1至Y8表示从均值线测量的峰值高度。

Arithmetic Average Roughness Height is usually measured in micro-inches and denoted by symbol “Ra”.
算术平均粗糙度高度通常以微英寸为单位测量，并用符号“Ra”表示。

There are various standards for the roughness of surfaces, set according to their type of application. The equipment used to measure the surface roughness is the so-called “profilometer” (which are available in the contact and non-contact types).
表面粗糙度有各种标准，根据其敷贴类型而定。用于测量表面粗糙度的设备是所谓的“轮廓仪”（有接触式和非接触式两种类型）。

In contact type profilometer the roughness is measured by moving the material under the profilometer stylus. However, modern equipment features non-contact measurements, leveraging the optical and ultrasonic technologies.
在接触式轮廓仪中，通过在轮廓仪触针下移动材料来测量粗糙度。然而，现代设备的特点是非接触测量，利用光学和超声波技术。

FLANGE AARH
法兰AARH

ASME/ANSI defined specific roughness standards for the flanges, as the flange face finish plays a pivotal role in gasket’s reliability and service life.According to the ASME/ANSI specifications, the serrated, spiral serrated, and concentric flange face finish should have an average roughness of 125 inch to 250 inch (3.2 m to 6.3 m).
ASME/ANSI规定了法兰的具体粗糙度标准，因为法兰表面光洁度对垫片的可靠性和使用寿命起着关键作用。根据ASME/ANSI规范，锯齿、螺旋锯齿和同心法兰表面光洁度的平均粗糙度应为125in至250in（3.2m至6.3m）。

The tool used to imprint a rough finish on the flange should have a radius of 0.06 inch (1.5mm) or larger. The groove density on the flange face should be from 45 grooves per inch to 55 grooves per inch (1.8 grooves/ mm. to 2.2 grooves/ mm.).
用于在法兰上压印粗糙表面的工具的幅度应为0.06英寸（1.5mm）或更大。法兰表面上的坡口密度应为每英寸45个凹槽到每英寸55个凹槽（1.8个凹槽/毫米到2.2个凹槽/毫米）。

These are the standards for semi-metallic and nonmetallic gaskets. If the average roughness of flange face is not according to the described standards, the contacting surfaces would not properly seal and the flanged joint may wear after some time working under pressure (resulting in loss of bolt joint tightness and a possible leakage).
这些是半金属和非金属垫片的标准。如果法兰表面的平均粗糙度不符合所述标准，接触面将无法正确密封，法兰节片在压强下工作一段时间后可能会磨损（导致锚杆节片的紧密性损失和可能的泄漏）。

The soft nonmetallic materials such as PTFE may be used for more comfortable facing and better creep resistance.
PTFE等软性非金属材料可用于更舒适的表面和更好的抗蠕变性。

ALLOWED AARH IMPERFECTIONS
允许AARH缺陷