Welding Repair of Steel Workpieces of Perkins Generator Set

Perkins generator set has low hardening tendency of low-carbon steel and low-carbon alloy steel. Perkins generator set has good weldability. With the increase of carbon content, the weldability decreases. After post weld heat treatment of high carbon steel and high carbon alloy steel, Perkins generator set is prone to hardening tendency due to the decrease of temperature of Perkins generator set.

Because of the hydrogen infiltration in the welding zone of Perkins generator set, ir and martensite brittleness and cracks are easily produced. The low carbon steel of Perkins generator set has good weldability, and no special process measures need to be taken. If the base metal or electrode composition is unqualified, the carbon or sulfur content is too high, or the workpiece with high rigidity is welded at low temperature of Perkins generator set, the Perkins generator set may have cracks. During operation, attention shall be paid to the selection and adjustment of flame, ignition and fire extinguishing, welding sequence and operation method to prevent defects.

The main difficulty in the repair of carbon steel welding in Perkins generator set is that the weld, especially in the arc pit, is easy to produce hot cracks. The main reason is that the carbon and sulfur content in the weld of Perkins generator set is high, especially the presence of sulfur. The low melting point iron sulfide produced in the crystallization process of Perkins generator set exists in the intergranular layer as liquid or semi liquid, forming very fragile interlayer, and cracks will occur once it shrinks.

Cold cracks may also occur at the weld, especially in the base metal near the weld zone. It occurs when Perkins generator sets are cooled to 300 ℃ or lower after welding, and some even after cooling for a period of time. The main reason is that with the increase of carbon content in the steel, the quenching tendency increases correspondingly, and the heating and cooling speed of the base metal near the weld is relatively high, leading to the low plastic hardening structure of Perkins generator set.

In addition, with the cooling of the welds of Perkins generator set, the hydrogen content in the welds and heat affected zone diffuses to the hot zone. In the hot zone, due to the role of hydrogen, the hardened structure is carbonized, that is, cracks are caused by shrinkage stress. It is worth noting that the heat treatment state of steel parts of Perkins generator set before welding repair will also affect the welding repair quality. Materials containing high carbon or alloy elements shall be subject to heat treatment before use. The damaged steel parts without annealing treatment are difficult to be repaired directly. The Perkins generator set is prone to crack. The cracks in the Perkins generator set steel can be divided into hot cracks when the welding metal is cooled and cold cracks caused by the embrittlement of the base metal near the welding area.

Starlight Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to sales@dieselgeneratortech.com we will pay highly attention on your question.