概述

summary

三桿蝶閥是一種密封型蝶閥，適用于冶金、化工、電力等行業(yè)，安裝在空氣、可燃氣體管路中，起切斷氣體介質(zhì)作用。以下是為某公司1006m3高爐制造的DN900三桿蝶閥閥體（見圖1），該工件采用Q235A鋼板焊接結(jié)構(gòu)，焊后經(jīng)退火去除焊接應力，再進行機械加工。因此對焊接要求較高，筆者根據(jù)實際生產(chǎn)總結(jié)如下，供參考借鑒。

The three rod butterfly valve is a sealed type butterfly valve suitable for industries such as metallurgy, chemical engineering, and power. It is installed in air and combustible gas pipelines to cut off gas media. The following is the DN900 three rod butterfly valve body (see Figure 1) manufactured for a company's 1006m3 blast furnace. The workpiece adopts a Q235A steel plate welding structure, and after welding, the welding stress is removed through annealing before mechanical processing. Therefore, the welding requirements are relatively high. Based on actual production, the author summarizes the following for reference.

圖1 三桿蝶閥閥體

Figure 1 Three Rod Butterfly Valve Body

（1）設(shè)計參數(shù)該閥體的相關(guān)參數(shù)如表1所示。

(1) The design parameters of the valve body are shown in Table 1.

表1 設(shè)計參數(shù)

Table 1 Design Parameters

（2）技術(shù)要求①本閥體焊接技術(shù)規(guī)范要求應符合YB/T036.11。②根據(jù)GB/T13927對本閥體進行強度試驗和氣密封性試驗。③焊縫全部為連續(xù)焊縫，所采用焊條為E4303，密封面堆焊A102。④焊縫高度應不小于相關(guān)件更薄鋼板厚度。⑤本閥體焊后應進行消除應力處理。

(2) Technical requirements: ① The welding technical specifications for this valve body should comply with YB/T036.11. ② According to GB/T13927, perform strength and air tightness tests on this valve body All welds are continuous, using E4303 welding rod and A102 surfacing welding on the sealing surface. ④ The height of the weld seam should not be less than the thickness of the thinnest steel plate of the relevant parts. ⑤ The valve body should undergo stress relief treatment after welding.

焊接工藝流程及焊前準備

Welding process flow and pre welding preparation

焊接工藝流程為焊前準備工作→焊接→外觀檢查→氣密性試驗。以下為焊前準備。

The welding process flow includes pre welding preparation → welding → appearance inspection → air tightness test. The following is the preparation before welding.

（1）焊件檢驗

(1) Weldment inspection

檢查閥體組對件的幾何尺寸是否符合圖樣設(shè)計要求。①檢查焊接填充材料（焊條或焊絲）是否與圖樣設(shè)計相符。②檢查焊接設(shè)備是否與焊接技術(shù)工藝參數(shù)相符。③清除焊接處的毛刺、油、水、銹等污物，使焊接處呈現(xiàn)金屬光澤。

Check whether the geometric dimensions of the valve body assembly match the design requirements of the drawing. ① Check whether the welding filler material (welding rod or wire) matches the design of the drawing. ② Check whether the welding equipment matches the welding technical process parameters. ③ Remove burrs, oil, water, rust, and other contaminants from the welding area to give it a metallic luster.

（2）焊接材料

(2) Welding materials

本閥體焊接所用的焊條為E4303（J422），焊接材料進廠必須憑質(zhì)量合格證明書入庫，J422焊條一般不烘干施焊，但庫存時間超過一年必須烘干施焊，烘干溫度100℃，時間為1h。

The welding rod used for the welding of this valve body is E4303 (J422), and the welding materials must be stored with a quality certificate when entering the factory. J422 welding rods are generally not dried for welding, but must be dried for welding if the inventory time exceeds one year, with a drying temperature of 100 ℃ and a time of 1 hour.

（3）設(shè)備選擇

(3) Device selection

焊接設(shè)備的選取如表2所示。

The selection of welding equipment is shown in Table 2.

表2 焊接設(shè)備

Table 2 Welding Equipment

焊接工藝

welding technology 

（1）焊接方法：焊條電弧焊。

(1) Welding method: arc welding with welding rod.

（2）接頭形式：角接頭（管板插入式，見圖2）。

(2) Joint form: angle joint (tube plate insertion type, see Figure 2).

（3）焊接位置：水平。

(3) Welding position: horizontal.

（4）焊接參數(shù)（見表3）：角接接頭可采用多層焊法或多層多道焊法。多層焊時，層焊道應選擇直徑較細的焊條。運條方法，應視間隙大小而定。間隙小時，可采用直線形運條方法；間隙較大時，可采用直線往復形運條方法。

(4) Welding parameters (see Table 3): Corner joints can be welded using multi-layer or multi-layer multi-pass welding methods. When multi-layer welding, the first layer of weld bead should be selected with a thinner diameter electrode. The method of moving the strip should depend on the size of the gap. When the gap is small, a linear strip transportation method can be used; When the gap is large, the straight reciprocating strip transportation method can be used.

表3 焊接參數(shù)

Table 3 Welding parameters

焊接順序為焊完層后，將焊道相對位置的焊道，用同樣的焊接方法施焊，閥體所有焊道層應全部焊完后，先清除其熔渣，然后用大直徑焊條和較大的焊接電流進行第二層焊接，運條方法采用直線形，以及幅度較小的月牙形和鋸齒形，并采用短弧焊接。

The welding sequence is as follows: after the first layer is welded, the weld beads in the opposite position of the weld beads are welded using the same welding method. After the first layer of all weld beads on the valve body is welded, the slag should be removed first, and then the second layer is welded using a large diameter welding rod and a large welding current. The welding method adopts a straight line, as well as a smaller crescent and serrated shape, and short arc welding is used.

為了保證焊接質(zhì)量和防止變形，應使層與層之間的焊接方向相反，焊縫接頭也相應錯開。

In order to ensure welding quality and prevent deformation, the welding direction between layers should be opposite, and the weld joints should also be staggered accordingly.

多層多道焊的焊接方法與多層焊相似，所不同的是每層焊縫由數(shù)道窄焊縫并列組成，焊接時應使用直線運條法。

The welding method of multi-layer and multi-pass welding is similar to that of multi-layer welding, except that each layer of weld is composed of several narrow welds in parallel, and the straight line welding method should be used during welding.

外觀檢查

Visual inspection

角焊縫的外觀成形目視應與母材圓滑過渡，光滑美觀，不得有氣孔、夾渣、咬邊等焊接缺陷。

The visual appearance of fillet weld shall be smooth and beautiful with smooth transition to the base metal. There shall be no welding defect such as pores, slag inclusion and undercut.

閥體密封面堆焊

Surfacing welding of valve body sealing surface

（1）堆焊方法

(1) Overlay welding method

焊條電弧焊；堆焊基面為凹形；堆焊位置：平放；堆焊電源：交直流兩用。堆焊參數(shù)如表4所示。

Welding rod arc welding; The welding base surface is concave; Welding position: flat; Welding power supply: AC and DC dual purpose. The welding parameters are shown in Table 4.

表4 堆焊參數(shù)

Table 4 Overlay Welding Parameters

（2）堆焊工藝

(2) Overlay welding process

堆焊前應清除焊道內(nèi)的毛刺、油、水、銹等污物；引弧與一般焊條電弧焊操作一樣，只是在起弧處做好標記，以利多層焊的一層圓滑搭接，從而保證堆焊的平整度，堆焊層數(shù)為3～5。運條同時存在三個基本動作：即直線動作、橫向擺動動作及焊條送進動作。在操作時，應根據(jù)熔池形狀與大小的變化，靈活地調(diào)整動作，使三者很好地協(xié)調(diào)，將熔池控制在所需的形狀與大小范圍內(nèi)，并使運條動作有利于熔渣的浮出。

Before welding, burrs, oil, water, rust, and other dirt should be removed from the weld bead; The arc striking operation is the same as that of general arc welding with welding rod, but the arc striking position is marked to facilitate the smooth overlap of the last layer of multi layer welding, so as to ensure the flatness of surfacing. The number of surfacing layers is 3-5. There are three basic actions for transporting the electrode simultaneously: linear action, lateral swing action, and electrode feeding action. During operation, the action should be flexibly adjusted according to the changes in the shape and size of the molten pool, so that the three can coordinate well. The molten pool should be controlled within the required shape and size range, and the strip movement should be conducive to the floating of slag.

運條橫向擺動時，應使兩側(cè)停留時間稍長些以保證堆焊層高度、寬度一致。收弧時，要注意應填滿弧坑，然后將焊條逐漸抬高，慢慢拉斷電弧。對一些易產(chǎn)生火口裂紋的材料，應將電弧的熄弧處引出焊道，以保證堆焊質(zhì)量。

When swinging horizontally, the stay time on both sides should be slightly longer to ensure that the height and width of the welding layer are consistent. When closing the arc, attention should be paid to filling the arc crater, and then gradually raising the welding rod to slowly break the arc. For some materials that are prone to fire cracks, the arc extinguishing point should be led out of the weld bead to ensure the quality of surfacing welding.

堆焊外觀檢驗不應有焊接缺陷。閥體整體焊完后進行退火，消除其內(nèi)應力。

There shall be no welding defect in the appearance inspection of surfacing. After the entire valve body is welded, annealing is carried out to eliminate its internal stress.

氣密性試驗

Air tightness test

閥體加工后與閥板組裝成形，進行氣密性試驗，將氣密性試驗工裝按工藝標準規(guī)定封閉好，然后向三桿蝶閥內(nèi)充1.1MPa壓縮空氣，5min后壓降滿足GB/T13927規(guī)定。

After the valve body is processed and assembled with the valve plate, a gas tightness test is carried out. The gas tightness test fixture is sealed according to the process standards, and then 1.1MPa compressed air is filled into the three-rod butterfly valve. After 5 minutes, the pressure drop meets the requirements of GB/T13927.