Types and characteristics of steel structure connections

一、钢结构的连接方法

First, the connection method of steel structure.

连接的作用是通过一定方式将板材或型钢组合成构件,或将若干构件组合成整体结构,以保证其共同工作。

The function of the connection is to combine the sheet metal or the section steel into the component in a certain way, or to combine some components into a whole structure, so as to ensure that they work together.

钢结构的连接方法可分为焊接连接、螺栓连接(铆钉连接)两种。

The connection method of steel structure can be divided into two types: welding connection, bolted connection (rivet connection).

二、焊缝连接

Two. Weld connection

（1）优点：

(1) advantages:

不削弱构件截面，节约钢材；

It does not weaken the cross section of members, saving steel.

可焊接成任何形状的构件，焊接间可直接焊接，一般不需要其他的连接件，构件简单，制造省工；

Can be welded into any shape of components, welding can be directly welded between, generally do not need other connectors, simple components, manufacturing labor-saving;

连接的密封性好，刚度大；

The sealing of the connection is good and the stiffness is large.

易于采用自动化，生产效率高。

It is easy to use automation and high efficiency.

（2）缺点：

(2) disadvantages:

位于焊缝附近热影响区的材质有些变脆；

The material in the heat affected zone near the weld is brittle.

在焊件中产生焊接残余应力和残余变形，对结构 工作有不利的影响；

Welding residual stress and residual deformation in weldments will have adverse effects on structure work.

焊接结构对裂纹很敏感，一旦局部发生裂纹便有可能迅速扩展到整个截面，尤其在低温下易发生脆断。

Welded structures are very sensitive to cracks. Once local cracks occur, they may rapidly extend to the entire section, especially at low temperatures.

常用的电弧焊的基本原理和设备

The basic principle and equipment of arc welding in common use

包括手工电弧焊、自动埋弧电弧焊和半自动埋弧电弧焊。

It includes manual arc welding, automatic submerged arc welding and semi automatic submerged arc welding.

1、手工电弧焊

1. Manual arc welding.

(1)原理：利用电弧产生热量熔化焊条和母材形成焊缝。

(1) principle: the arc is used to generate heat to weld the electrode and the base metal to form the weld.

（2）优点：设备简单，操作灵活方便，适于任意空间位置的焊接，特别适于焊接短焊缝。

(2) Advantages: simple equipment, flexible and convenient operation, suitable for welding in any space position, especially suitable for welding short welds.

（3）缺点：生产效率低，劳动强度大，焊接质量取决于焊工的精神状态与技术水平，质量波动大。

(3) Disadvantages: low production efficiency, labor intensity, welding quality depends on the welder's mental state and technical level, quality fluctuations.

2、埋弧焊（自动或半自动）

2. Submerged arc welding (automatic or semi-automatic)

（1）原理：埋弧焊是电弧在焊剂层下燃烧的一种电弧焊方法。

(1) principle: submerged arc welding is an arc welding method under which the arc burns under the flux layer.

（2）优点：自动化程度高，焊接速度快，劳动强度低；电弧热量集中，熔深大，热影响区小；工艺条件稳定，焊缝的化学成分均匀，焊缝质量好，焊件变形小。

(2) Advantages: high degree of automation, fast welding speed, low labor intensity; arc heat concentration, deep penetration, heat affected zone small; stable process conditions, uniform chemical composition of the weld, good weld quality, weld deformation is small.

（3）缺点：装配精度要求高，设备投资大，施工位置受限等。

(3) disadvantages: high assembly accuracy, large investment in equipment, limited construction position, etc.

（4）焊丝的选择：埋弧焊的焊条应与焊件钢材相匹配，如：Q235-H08、H08A、H08MnA; Q345、Q390-H08A、H08E、H08Mn等。

(4) Selection of welding wire: submerged arc welding electrode should be matched with welding steel, such as: Q235-H08, H08A, H08MnA; Q345, Q390-H08A, H08E, H08Mn, etc.

3、焊条的表示方法：E后面加4个数字

3. Method of welding electrodes: add 4 numbers after E.

E—表示焊条(Electrode)

E - indicating electrode (Electrode)

前两位数字为熔敷金属（焊缝金属）的最小抗拉强度（N/mm2)

The first two digits are the minimum tensile strength of deposited metal (weld metal) (N/mm2).

第三位数字表示适用于哪些焊接位置，0与1表示焊条适用于全位置焊接（平、立、仰、横），2表示焊条适用于平焊及平角焊，4表示焊条适用于向下立焊；

The third digit indicates which welding positions are suitable for, 0 and 1 indicate that the electrode is suitable for all-position welding (horizontal, vertical, inverted, horizontal), 2 indicate that the electrode is suitable for flat welding and flat fillet welding, 4 indicate that the electrode is suitable for downward vertical welding;

第三位与第四位组合时，表示焊接电流种类及药皮类型。

The combination of third and fourth represents the type of welding current and the type of coating.

对于低合金钢焊条，短画线后面的符号表示熔敷金属化学成分分类代号（GB/T 5117-1995及GB/T 5118-1995）。

For low alloy steel electrodes, the symbol behind the short drawing line represents the chemical composition classification code of the deposited metal (GB/T 5117-1995 and GB/T 5118-1995).

焊条的选择

Selection of electrode

焊条应与焊件钢材相适应；不同钢种的钢材焊接，宜采用与低强度钢材相适应的焊条。如：

The electrode should be suitable for the steel of welding parts, and the electrode suitable for the low strength steel should be used for the welding of different steel grades. Such as:

Q235钢——E43型焊条（E4300--E4328)

Q235 steel -- E43 type electrode (E4300--E4328)

Q345钢——E50型焊条(E5000--5048)

Q345 steel -- E50 type electrode (E5000--5048)

Q390、Q420钢——E55型焊条(E5500--5518)

Q390, Q420 steel - type E55 electrode (E5500--5518)

4. 焊缝的方位和要求

4. orientation and requirements of welds

焊缝符号与标注方法

Weld symbols and marking methods

在钢结构施工图上要用焊缝代号标明焊缝形式、尺寸和辅助要求。

In the steel structure construction drawing, the weld code should be used to indicate the form, dimension and auxiliary requirement of the weld.

焊缝代号主要由图形符号、辅助符号和引出线等部分组成。

The code of weld is mainly composed of graphic symbols, auxiliary symbols and lead lines.

具体有关代号规定和详细说明，可参照《建筑结构制图标准》（GB/T 50105—2001）和《焊接符号表示法》（GB 324—88）。

Specific code requirements and detailed description can be referred to the "Building Structure Drawing Standards" (GB/T 50105-2001) and "Welding Symbol Representation" (GB 324-88).

6、 焊缝缺陷

6. Weld defects

焊缝质量检验等级和焊缝质量等级

Weld quality inspection grade and weld quality grade

焊缝质量检验等级除对外观和尺寸进行检查外，还应进行焊缝内部质量的检验。当采用超声波探伤时，检验等级分为A、B、C三级；当采用射线探伤时，检验等级分为A、AB和B三级。

In addition to inspecting the appearance and dimension, the inspection grade of weld quality should also inspect the internal quality of the weld. When ultrasonic testing is used, the inspection grade is divided into three grades: A, B and C, and when radiographic testing is used, the inspection grade is divided into three grades: A, AB and B.

根据对焊缝质量检验等级的要求不同，把焊缝质量分为一、二、三级。每个等级的检验内容不一样。

According to the requirements of weld quality inspection level, the weld quality is divided into one or two and three grades. The test content of each grade is different.

三、螺栓链接

Three. Bolt link

1.普通螺栓连接

1. ordinary bolt connection

根据对孔壁质量要求，将螺栓孔分为两类：Ι类孔（A、B级)和∏类孔（C级）。

According to the quality requirements of the hole wall, the bolt holes are divided into two types: class_ (A, B) and class_ (C).

Ι类孔的螺栓连接，其抗剪和承压强度比∏类孔的高，但是Ι类孔的制造费工，成本高。

The shear and compressive strength of the bolted connection with the_-type hole is higher than that of the_-type hole, but the manufacture of the_-type hole is costly and costly.

A、B级螺栓孔对制孔的要求比较高，但安装困难，成本高，一般很少使用；C级螺栓孔制孔粗糙、不精确，但安装方便，目前在钢结构中普遍使用。

Class A and B bolt holes have high requirements for drilling, but they are difficult to install, expensive and seldom used in general; Class C bolt holes are rough and imprecise, but easy to install, so they are widely used in steel structures.

2、高强度螺栓

2. High strength bolts

高强度螺栓连接传递剪力的机理和普通螺栓连接不同，普通螺栓是靠螺栓抗剪和承压来传递剪力的，而高强度螺栓连接首先是靠被连接板件间的强大摩擦阻力传递剪力的。

The mechanism of shear transfer in high strength bolted connection is different from that in ordinary bolted connection. The shear transfer in ordinary bolted connection depends on the shear resistance and compression of bolts.

安装时通过特别的板手，以较大的扭矩上紧螺帽，使螺杆产生很大的预拉力。高强螺栓的预拉力把被连接的部件夹紧，使部件的接触面间产生很大的磨擦力，外力通过摩擦力来传递。这种连接称为高强度螺栓摩擦型连接。

During installation, the screw is tightened with a large torque by a special plate hand, which makes the screw produce a great pre-tension. The pre-tension force of the high-strength bolt clamps the connected parts so that a great friction force is generated between the contact surfaces of the parts, and the external force is transmitted by the friction force. This connection is called the high strength bolt friction type connection.

螺栓的性能统一用螺栓的性能等级表示，如4.6级、8.8级、 10.9级。

The performance of bolts is expressed in terms of the performance grade of bolts, such as grade 4.6, grade 8.8 and level 10.9.

小数点前的数字表示螺栓材料的抗拉强度，小数点及后面的数字表示屈强比。

The number before the decimal point indicates the tensile strength of the bolt material, and the decimal point and the number after it indicates the yield ratio.

4.6级、8.8级、 10.9级螺栓强度分别属于400N/mm2 、800N/mm2 、1000N/mm2级。

The strength of bolts of grade 4.6, grade 8.8 and grade 10.9 belong to 400N/mm2, 800N/mm2 and 1000N/mm2 respectively.

C级螺栓为4.6级或4.8级，由Q235钢制造。

Grade C bolts are grade 4.6 or 4.8, made of Q235 steel.

A、B级螺栓为5.6级或8.8级，采用低合金钢或再经热处理后制成。

A and B bolts are grade 5.6 or 8.8, which are made of low alloy steel or after heat treatment.