By Gregory Havel
One of the most common connections used today in structural steel fabrication and erection is arc welding. The strength of these connections depends on good metal-to-metal contact; the cleanliness of the metal surfaces; the proper size and alloy of the welding electrode or wire; the proper amperage (electric current); proper size of the finished weld, which may require more than one pass by the welder; the proper technique; and the skill of the welder. A skillfully executed weld will have the same or greater strength than the steel parts that it connects.
Photo 1 shows two tubular beams that have been welded to an H-column. The white paint has been ground from the steel in the areas to be welded and will be replaced when welding has been completed, inspected, and approved. The welding on the beam on the right has been completed, and it required multiple passes by the welder. The welding on the beam on the right had one pass completed, and it will require an additional pass by the welder.
(1) Photos by author unless otherwise noted.
Arc welding can be done with a hand-held electrode and a ground clamp connected by cables to a welding machine. This is the process used most often in making structural steel connections in the field; it was used for the welds shown in photo 1.
也可以使用由氩气，氦气和二氧化碳等惰性气体的混合物屏蔽的电力式电极进行电弧焊接。由于此过程中使用的机器很笨重，必须位于焊接位置附近，因此它们通常用于制造圆柱，大梁和横梁的商店中。而且，在建筑工作现场建立连接的频率较低。照片2是使用带有惰性气体屏蔽的电力式电极的弧形焊接机器人的照片。这种类型的焊接工艺也可以使用手持电极而不是机器人机械进行。
(2) Photo courtesy of FANUC Robotics Deutschland.
Photo 3 shows a welder connecting a bar joist to the setting plates in the top of masonry walls. He is using an arc welder with a ground clamp and a hand-held electrode to complete the connection.
(3)
照片4显示了一块完整的焊接，在检查和绘画后，将杆托梁连接到钢梁。
(4)
请注意，照片4中所示的焊缝将钢筋托梁固定在梁上并有助于稳定结构，但它们不支持条形托梁或其负载的重量，而照片1中显示的焊缝是剪切的，并支撑梁的全部重量及其负载。
柱和大梁之间的焊接连接是由工程师设计的，包括要沉积的焊接类型，要使用的电极或电线的合金和大小，用于制造焊接的安培（电流）以及数量完成关节所需的强度所需的焊接通道。
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A common engineering design requires the ends of girders bearing on masonry or concrete to be lapped at least six inches (152 mm) onto steel bearing plates that are grouted into the masonry or concrete and are designed to be connected by two ¼-inch (6.35 mm) × two-inch (51 mm) fillet welds. Those bearing on structural steel are lapped at least four inches (101 mm) onto the steel and are connected by two ¼-inch (6.35 mm) × two-inch (51 mm) fillet welds.
托梁和大梁之间的焊接连接板或砌体墙轴承板的焊接板为2英寸（3.18毫米），乘以一英寸（25毫米）的圆角焊缝，如照片4所示，除非工程师需要较强的焊缝。
For more information on electric arc welding processes, and structural steel fabrication and erection, do an Internet search for the following:
- Welding.
- Robotic welding.
- Welding techniques.
- 电弧焊接。
- ANSI AWS B2.1-1-211。
- 美国焊接协会www.aws.org（8669 NW 36 Street＃130，Miami FL 33166），P：（800）443-9353或（305）443-9353。
- AWS D1.1 / D1.1M: 2015: Structural Welding Code—Steel, 2015 edition.
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格雷戈里·哈维尔（Gregory Havel）is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 35-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 35 years of experience in facilities management and building construction; and has presented classes at FDIC.
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