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30
2021-08
Talk about the ubiquitous, flickering welding holes.
The so-called pores refer to the holes formed by the gas in the weld. Porosity is a common defect in welds, which reduces the effective cross-sectional area of welds, causes stress concentration, destroys the density of welds, and causes weldments to fail. There are surface pores in welds, internal or root pores, such as internal pores in electroslag welding welds, and penetrating pores. From the distribution point of view, there are single pores and piles of dense pores. Gas forming pores include hydrogen, nitrogen, carbon monoxide gas and water vapor. Hydrogen, nitrogen gas is dissolved in the metal at high temperature, in the process of solidification, hydrogen, nitrogen gas in the liquid-solid stage solubility occurs suddenly.
2021-08-30
30
2021-08
49 welding knowledge points solve the welding problems of common iron-based materials
Weldability and its test evaluation: 1. Welding: By heating or pressurizing, with or without filler material, the two objects are combined between atoms to form an integral whole process. 2. Weldability: refers to the ability of homogeneous or heterogeneous materials to be welded to form a complete joint and meet the expected use requirements under the manufacturing process conditions. 3. The four factors that affect weldability are: material, design, process and service environment. 4. The principle of evaluating weldability mainly includes: ① evaluating the tendency of welding joint to produce process defects, so as to provide basis for formulating reasonable welding process; ② evaluating whether the welding joint can meet the structural requirements
2021-08-30
25
2021-08
What is welding stress? Learn these three methods to remove easily!
1. What is welding stress Welding stress is the stress of welded components due to welding. The internal stress generated in the weldment during the welding process and the change in the shape and size of the weldment caused by the welding thermal process. The uneven temperature field of the welding process and the local plastic deformation and the organization with different specific volume caused by it are the root causes of welding stress and deformation. When the uneven temperature field caused by welding has not disappeared, this stress and deformation in the weldment is called transient welding stress and deformation; the stress and deformation after the welding temperature field disappears is called residual welding stress and deformation. In the absence of external forces, the welding stress in the weldment
2021-08-25
25
2021-08
According to different construction methods, piles can be divided into prefabricated piles (prestressed pipe piles) and cast-in-place piles (cast-in-place drill pipe piles). Both are widely used in soft soil foundation and deep buried foundation, which have the characteristics of high bearing capacity, good stability, small settlement and low material consumption, which can effectively meet the requirements of building for foundation strength, deformation and stability. The two types of piles have their own characteristics, different construction methods, different mechanical equipment and construction techniques, different mechanisms of pile and soil, and different scope of application. This article will compare these two types of piles, analyze their advantages and disadvantages and applicability, so as to determine whether to choose prestressed pipe piles or bored piles
2021-08-25
25
2021-08
Drill pipe drilling into piles, drill pipe length is not long enough to do
How to deal with the situation that the length of the drill pipe is less than the design length when the cast pile is drilled with the drill pipe? The problem encountered by this colleague is a bit serious. After testing bored piles in their project, they found that the length was not enough, some of them were 2 meters in length, and some of them were 4 or 5 meters in length. The types of bored piles are soil foundation, friction pile and single pile bearing capacity. To this end, we give the solution: Answer 1: test qualified? qualified, deduct and impose the construction unit unfinished construction project fine. If it is not qualified, please submit the detailed information (marked with short pile drawing, test is not qualified) to the design institute, and the design scheme will be issued.
2021-08-25
25
2021-08
According to the Qinghai Provincial Emergency Management Department, at 12:10 on August 14, 2021, a mud collapse accident occurred in the Chaidar Coal Mine of Xihai Coal Company, Gangcha County, Haibei Prefecture, Qinghai Province. There are 21 underground workers. After the accident, the Chaidar Coal Mine Rescue Team immediately organized rescue and rescued a total of 2 people, of which 1 died, the other 1 was not life-threatening, and 19 people were trapped. At present, the coal mine rescue team and the fire brigade of Haibei Prefecture have gone to the scene of the accident to carry out rescue. (head office reporter Li Yonghui, Liu Cheng, Mao Baowu) [State Administration of Mine Safety Supervision] August 14, 2021, Qinghai Xihai Coal Development Co., Ltd. Chai
2021-08-25
25
2021-08
On August 19, 2021, a roof fall accident occurred in Qingshuiying Coal Mine in Ningxia, and all 4 people trapped were safely lifted to the well!
2021-08-25
25
2021-08
On August 21, 2021, one roof accident occurred in Manqiaogou Coal Mine of Manqiaogou Mining Industry in Tumote Right Banner, Inner Mongolia, killing one person.
2021-08-25
17
2021-08
How to Repair Geological Drill Pipe and Drill Bit-Yikuang Science and Technology
The essence of geological drill pipe and drill bit is to make the impactor dive into the hole during the drilling process to reduce the energy loss caused by the impact work transmitted by the drill pipe, thereby reducing the impact of the hole depth on the drilling efficiency. The drilling apparatus for drilling a potential hole is a potential hole drill. In China, yq-80,yq-100,qz-165 and other types of geological drill pipe are commonly used in underground mines. 1. in the process of drilling geological drill pipe and drill bit, the propulsion beam should be tightly attached to the rock and do not move. If the propulsion beam moves in the borehole, bending stress will be generated, which in extreme cases can cause abnormal fracture of the drill pipe. 2. not allowed in advance
2021-08-17
17
2021-08
PDC bit selection, how to choose the most cost-effective bit?
An important concept when choosing a drill bit is that regardless of the quality of the drill bit or drill bit, the economics of drilling should always be measured in terms of cost per foot. Engineers and salespeople should correctly choose the most economical drill bit per unit depth to reduce costs and obtain higher profits. In particular, the price of a PDC bit may be 20 times the price of a milling bit and four times the price of a tire bit. But in many cases, PDC bits are a more economical option because PDC bits usually have a faster drilling speed (ROP) or better durability (longer). Again, there are no absolute advantages or disadvantages to choosing a drill bit
2021-08-17
