Copper Strip is a kind of metal element, the product specification has 0.1 ~ 350 ~ 250mm various state copper strip product, mainly uses in the production electric appliance component, the lamp head, the battery Cap, the button, the seal piece, the connector, mainly uses in the electric conduction, the heat conduction, the corrosion resistance equipment. Such as electrical components, switches, washers, gaskets, electric vacuum devices, radiators, conductive base materials and Automotive Water Tanks, heat sinks, cylinder pieces and other parts.

However, in the production process there will be some problems, resulting in copper strip will have some defects, the following we will specifically analyze the problems in different circumstances, as well as treatment measures.

1. DESCRIPTION:

In the process of drawing and casting, the edge of slab in horizontal continuous casting appears irregular cracking

CAUSE/MECHANISM:

1)The copper water in the mould can not crystallize normally because of frequent stop times or long stop time in the process of melting and casting

What to do:

Emergency Measures:

1) check whether the casting machine is working properly and the process parameters are set correctly;

2) check the use of the Mould; 

3) selectively cut off the flow or scrap and return to the furnace according to the degree and position of the edge crack of the casting slab; 4) check whether the temperature of the cooling water in and out is in accordance with the process requirements;

Control Measures:

1) strengthen the check of equipment before shift to ensure the working status of the casting machine;

 2) set the process parameters of the casting machine correctly according to the actual production situation; 

3) install the crystallizer in place and check the using status of the crystallizer in time;

2. DESCRIPTION:

There is a long black stain which can not be washed off after strip rolling

CAUSE/MECHANISM:

1) rolling oil use time is too long, containing impurities pollution copper strip; 

2)emulsion time is too long, emulsion is dirty;

What to do:

Emergency Measures:

Control Measures:

1) check the rolling oil regularly, add diatomite and active clay every shift, do the filtration well; 

2) change the emulsion in time (at least once a month) according to the use of the emulsion;

3. DESCRIPTION:

One-sided uneven edge, similar to the regular wave-like defects

The reason/mechanism:

 1) the uneven deformation between the edge and the middle during rolling. 1) the two sides of the rolls are not adjusted in accordance with each other, the thickness of the two sides of the incoming material is not uniform, and the single side waves are easy to appear when the properties are not uniform 2. Uneven Cooling and lubrication on both sides during rolling; 3. Misalignment of feed or misalignment of rolled parts;

What to do:

Emergency Measures:

1) stop rolling, check whether the rolled piece is in the center, whether the adjustment of both sides is consistent, whether the lubrication is uniform, and make the corresponding adjustment in time;

Control Measures:

1) each working procedure should cooperate with each other to control the lateral tolerance, and the fluctuation should be marked on the process cards; 

2) the billet should be annealed horizontally evenly; 

3) the lubrication should be rationally arranged along the roll surface with the flow rate and strength; 

4) The roll should be grinded and replaced in time;

4. DESCRIPTION:There are regular marks on the surface of Copper Strip with a certain angle of inclination

The reasons and mechanism are as follows: 

1)The oil film is broken because of the high rolling rate; 

2)The roller is defective because of the lack of lubrication during rolling; 

Measures: Emergency Measures: 1) Stop Rolling immediately, adjust the gap between rolls, reduce the rate of processing;

 2) Replace Rolls; Control Measures: 1) according to the established rolling system, appropriately increase the number of rolling passes, in order to reduce Michitsugu processing rate;

 3) replace rolls in a timely manner;

5. Description: There are some small pits on the surface of copper strip, sometimes the distribution has regular 

cause/mechanism

1. Copper powder and other particles are adhered to the work roll and oil removing roll of the rolling mill, and small pits are formed on the surface of Copper Strip during its operation.

 2. Hard particles are adhered to the rubber roll of the pickling line, and press pits are formed during the operation of Copper Strip Treatment measures emergency measures: Equipment immediately stop running, check the roll system, if the surface of the roll has hard particles, timely cleaning or roll change; Control Measures: 1) check each work roll and back-up roll before shift if there is foreign body, if there is any abnormality, deal with it in time; 2) in the production process, must check the production condition of the head of each material roll to ensure that the whole copper strip is qualified;

6. Feature description: The reason/mechanism of regular damage on the surface of copper strip in the length direction: 

1. The surface of copper strip is bruised by sticking copper on the work roll and oil removing roll of rolling mill; 

2. The work roll of rolling mill is not polished well; 

3, acid cleaning process of roll with stolen goods; 

Emergency Measures: 1) immediately stop the machine, and carefully check the status of the work roll, etc. 2) the copper strip has been contused according to the specific conditions of the system or scrap; control measures: 1) the management of mold norms, each shift to check the roll and track the use of the situation before work; 2) do incoming inspection to ensure that this process does not add to the process defects; 3) each shift to ensure that the industrial hygiene of the equipment is good;

7.copper tape layer and layer stuck together, slightly open when there is a clear "squeak" sound, after the open bond has a clear white mark, it is difficult to cut and separate the serious copper strips because of 

the following reasons: (1) the vacuum state of the copper strips is difficult to separate due to the volatilization or carbonization of some un-cleaned rolling media at high temperature; 

2. Too much tension in rolling mill or pickling line will lead to sintering of Strip surface after annealing. 

3. Too High annealing temperature, too long time, copper strip too soft, combined more closely; Treatment Measures 

Emergency Measures: 1) slightly burning and sticking can be determined to continue the next process; 2) burning and sticking serious direct return smelting and cutting with a cutting machine, and then re-melting; control measures: 1) appropriately reduce the annealing temperature and annealing time of copper strip; 2) strengthen the middle process of various media (mainly rolling oil) cleaning; 3) control the tension of rewinding;

8. Description: The INGOT is dark brown with irregular cracks in the side and center. 1. The impurity elements in the ingot exceed the standard (such as PB, etc.) , and there are more non-solid-soluble substances 

2. The quantity of cooling water does not match the casting speed; 

3. The temperature of copper water in the melting furnace is too low; \

4. The surface of mould is rough and the inner wall is slagged; Emergency Measures: 1) strictly check the composition of each furnace, less charge as far as possible in the furnace copper water cast out, and then cut into small sub-fractional furnace for remelting; 2) smelting furnace copper water temperature rise, holding casting; control measures: 1) the raw material strictly check, each furnace according to requirements control components; 2) according to process requirements control casting speed and cooling water volume; 3) ensure that the process of copper melting furnace copper water temperature control in the process requirements; 4) after each furnace copper mold mold in a timely cleaning, and coated carbon powder coating;

9. The reason/mechanism is: 

1. When the copper liquid crystallizes, the liquid cavity is deeper because of the improper matching of cooling and drawing speed;

 2. The liquid feeding in the middle part of the ingot tail is not timely Emergency Measures: 1) according to the depth of the shrinkage hole cut off a part, if the length is more than 3.8 m, then can flow into the next process; 2) the shrinkage hole is too deep, resulting in length less than 3.8 m, then directly cut into small sections and separate remelting; control measures: 1) control the flow and pressure of cooling water to ensure the temperature difference of cooling water in and out of the water; 2) in the final stage of casting, speed down casting according to the process, and stop the machine for a period of time to ensure the completion of feeding;

10. Description: there are gas holes on the surface of Ingot, which are caused by the indeterminate depth of the surface. 

The mechanism is as follows: 1. The gas can not be removed by spraying fire in melting process, and the gas can not be discharged in time in casting process; 2. The copper water is not protected effectively in the casting process, which causes the copper water to be aspirated; 3. The vibration is not opened in the casting process, which leads to the bad exhaust effect; 4. The casting speed is faster and the exhaust gas is not timely; Sentence is too long, please supply a shorter sentence

 11.Feature description: Brass semi-continuous casting billet appears hollow parallel to the width direction after sawing, usually the whole ingot has the 

CAUSE/MECHANISM: 1. Casting speed is too fast, the middle copper liquid is not solidified in time, but after the crystallizer, the cooling speed of cooling water in mould is too fast, and the pouring temperature is unreasonable Treatment measures: emergency measures: 1) adjusting the process, timely recharging the Ingot for the above problems; 1) adjusting the tapping temperature of H65 to 1070 °c (1080 °C) , H62 to 1045 °c (1055 °c) , and the number of H65 over 1080 °c (1080 °c) , changing the original one-time fishing slag into two-time fishing slag;

12. Description: There are white borax particles on the surface of the INGOT, sometimes the depth of embedding is deep, 

the reason/mechanism is not easy to remove: The casting personnel add borax in the wrong way, resulting in powder borax in the mold to accumulate into blocks did not melt; Measures: Emergency Measures: 1) using a polishing machine or iron brush to remove the borax particles on the surface of the Ingot; 2) casting surface borax difficult to clean the ingot in batches return to the furnace; control measures: 1) carefully check the state of borax before casting to ensure the drying of Borax (drying through the oven) ; 2) casting personnel in the addition of powder borax should be a small number of times, so that borax evenly covered in the liquid surface, to ensure borax can be fully dispersed and melt; 3) using a new way of adding, melting borax;

13. Description: White particles appear in the INGOT during hot rolling, but they often gather together to form strip. 

REASON/MECHANISM: 1. The grain size of borax is not uniform during casting, during hot rolling, some of the massive borax adhered to the surface layer is wrapped by copper strip deformation with the deformation of the INGOT Treatment Measures Emergency Measures: 1) continue rolling, determine its influence in coiling, can adjust copper strip milling surface amount; control measures: 1) regulate the adding way of Borax: a few times, and fully crush borax particles; 2) adopt new equipment to melt borax before adding; 3) do simple cleaning and grinding to ingot surface before hot rolling;

14. Feature description: strip-shaped peeling occurs after rolling of brass strip, peeling layer can be torn off by hand, there is a layer of foreign matter under peeling layer, the reason/mechanism: there is inclusion defect in Ingot, the extension property of inclusion and Matrix is different after rolling, which causes peeling; 

Measures: Emergency Measures: 1) stop inspection, if the defect in the head or tail, cut it off; 2) if the defect is serious and in the middle, communicate with quality control personnel, or remanufacture or return to the furnace; control measures: 1) power cut while casting static for a period of time to wait for impurities floating or sinking, will dredge the slag clean; 2) smelting furnace to clean the furnace wall frequently, after using a period of time to re-blow the furnace to ensure the copper water clean; 

Source: Copper Alloy Casting

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