Operation instructions for technical measures for

Winter welding construction technical measures operation instructions

1.1 Technical specification for welding of thermal power plants (dl/t)

1.2 Standard for quality inspection and evaluation of thermal power plants welding (1996 edition)

1.3 Technical specification for welding heat treatment of thermal power plants (dl/t)

1.4 "Quasi mandatory provisions of engineering construction standard due to large force value when tensile these samples" electric power engineering part (2006 Edition)

1.5 Code for safety work in electric power construction thermal power plant (dl5009.)

1.6. Technical specification for welding of building steel structures (jgj-)

2 Project overview

the plant area of Shanxi Shanyin 2 300MW coal gangue comprehensive utilization power generation project is located about 1.3km northwest of beizhouzhuang Town, Shanyin County, Shanxi Province. The multi-year average temperature is 7.6 ℃, the extreme maximum/low temperature is 38 ℃/-31.6 ℃, the multi-year average precipitation is 362.4mm, the average relative humidity is 52%, the multi-year average wind speed is 2.6m/s, the maximum wind speed is 20 m/s, the average number of strong wind days is 17.4d, and the average number of snowfall days is 21.2d

3. Preparation purpose

in order to ensure the safety and quality of winter welding construction of unit 2 of Shanxi Shanyin 2300mw coal gangue comprehensive utilization power generation project, and in combination with the characteristics of local welding construction environment in Shanyin, this welding construction technical measure is specially formulated

4. Technical requirements and measures

4.1 technical requirements:

when any of the following conditions occur in the welding environment and there are no effective protective measures, welding is strictly prohibited:

a) the wind speed in the welding area during GTAW welding is not greater than 2 m/s, and the wind speed during SMAW welding is not greater than 8 m/S

b) the relative humidity within 1m of the welding arc area shall not be greater than 90%

c) the weldment has water, is exposed to rain or is in contact with 3.1 the lifting control deviation of the lifting mechanism should be 0 ~ 25mm to snow and fog

d) the temperature is lower than the following temperature:

a- Ⅰ - 10 ℃

A-Ⅱ、A-Ⅲ、B-Ⅰ 0℃； Press the "detection" key

b- Ⅱ, b- Ⅲ 5 ℃

(Class C is not specified)

e) there is ventilation in the welded pipe

4.2 technical measures

in accordance with the specified environmental requirements of wind speed and humidity, as well as the minimum temperature and requirements for the welding construction of various steel grades, and in view of the actual situation of the winter construction of the project, the following measures are specially proposed to be implemented in the construction:

4.2.1 construction measures

4.2.1.1 when the environmental temperature is lower than the requirements in Article 4.1, the weldment must be properly preheated to improve the temperature of the weldment

4.2.1.2 at low temperature of 0 ℃ and below, the preheating temperature of heat-resistant steel pipes, pipe fittings with wall thickness ≥ 6mm and plates with thickness ≥ 34mm can be increased by () ℃ according to the specified value during welding

4.2.1.3 low alloy steel pipes with a wall thickness of 6mm and carbon steel pipes with a wall thickness of 15mm shall be properly preheated during welding at -10 ℃ and below

but the price is also high. 4.2.1.4 when welding large-diameter b-iii steel pipes with a minimum ambient temperature of 5 ℃, increase the ambient temperature by heating the heat emitted by electric heating and iodine tungsten lamp in the cold proof and wind proof shed

4.2.1.5 during the welding of important steel structures, when the environment of the welding operation area is lower than 0 ℃, the base metal in each direction of the welding area of the component shall be greater than or equal to 2 times the thickness of the steel plate and not less than 100mm, and shall not be welded until it is heated to more than 20 ℃, and shall not be lower than this temperature during the welding process. The actual heating temperature shall be determined according to the structural characteristics of components, steel type, quality grade, weldability, diffusive hydrogen content of deposited metal of welding materials, welding method, welding heat input and other factors. The heating temperature shall be higher than the welding preheating temperature under normal temperature, and the operation plan shall be formulated by welding technicians and implemented after approval. The operation plan shall ensure that the welder's operation skills are not affected by the low temperature of the environment, and necessary thermal insulation measures shall be taken for the components