Casting Inspection And Testing | Non Destructive Testing (NDT) | Destructive Testing (DT) Method For Casting | Casting Repairing

Casting Inspection | Casting Testing | Casting Repair |

(a) Casting Inspection And Testing Method

What are casting inspection and testing techniques/methods used in the foundry?

Final casting produced from any casting process should have the exact functional, mechanical, metallurgical and aesthetic value that the customer demands and expects from the manufacturers.

Casting inspection and testing consist of using various destructive and non-destructive methods to determine the casting defects of the solidified casting checking its casting surface and subsurface defects, porosity, cracks, inclusions, oxides, foreign material, cold laps, voids, chemistry errors, incomplete sections, unfilled sections, shrinkage, unevenness, tearing, flaws, warpage, dimensions, mismatch, accuracy, contours, surface finish, mechanical properties, strength (tensile, compressive, shear and ultimate) and visual appearance.

I have discussed below both destructive (metallurgical, mechanical and chemical testing) and non-destructive techniques (ultrasonic, X-ray, dye penetration, dimensional analysis and leakage) with a diagram used in the casting process to determine if the casting is manufactured to its highest reliable quality before dispatching it to the customers.

Testing and inspection of casting components made from investment casting, shell casting and die casting become important as many casting products are used in aerospace, space industry, automobile, defence, marine and military where reliability, function and quality of casting components are of top priority.

Casting Inspection And Testing Method Checklist

List down the checklist for casting inspection and testing method?

Visual inspection testing method for casting.
Magnetic particle inspection and testing method.
Ultrasonic inspection and testing method for casting.
Water and Air pressure testing method to check leakage in casting.
Dye penetrative test method for testing and inspection.
Eddy's current inspection and testing method for castings.
X-Ray and Ɣ-Ray (Radiographic examination and testing).
Metallurgical and mechanical testing method.
Spectrographic atomic absorption inspection and testing.

I have explained the above inspection and testing methods below in detail.

Non-Destructive Testing Method For Casting

What are non-destructive testing (NDT) methods for casting?

Visual inspection testing and inspection method.
Radiographic examination such as X-ray and Ɣ-ray.
Ultrasonic inspection and testing method.
Eddy's current inspection and testing method.
Dye penetration inspection and testing method.
Magnetic inspection and testing method.
Water test to detect leakage.
Air pressure test to detect leakage.

I have discussed the listed non-destructive testing method in detail below.

Destructive Testing (DT) Method For Casting

What are destructive testing (DT) casting inspection and testing methods for casting?

Mechanical testing method.
Metallurgical testing method.
Spectrographic atomic absorption and composition of molten metal.

I have discussed the destructive testing method for casting in detail below.

Inspection & Testing Methods

The stages of inspection and testing in the casting process are as follows:

Control over the composition of molten metal.
Dimension and tolerance inspection of casting.
Surface quality and surface finish examination.
Mechanical properties testing.
Non-destructive testing.

Composition of Molten Metal And Spectrographic Atomic Absorption (Destructive Technique DT Method)

Spectrographic atomic absorption consists of checking the chemical composition of the metals (copper, zinc, aluminium, brass, lead and tin) in the casting.

Done by spectroscopy by the optical emission spectroscopy technique. In this process atoms in a sample are excited by energy that sparks formed between the sample and electrodes.

Qualitative and quantitative analysis can be made by measuring peaks of the spectrum.

Visual Inspection of Casting (Non-Destructive Technique NDT Method)

What are visual inspection techniques, inspection and testing used for casting?

Visual inspection is carried out by the quality engineer in the foundry to determine defects in the final casting such as cracks and warpage.

Visual inspection is done immediately after the casting has been removed from the mould and after the heat treatment of the casting.

Visual inspection is a non-destructive testing (NDT) method to check misrun, cold-shut, cracks, incomplete solidification sections, unfilled outer sections, foreign particles on the outer side of casting parts, moulding flaws, uneven fusion, uneven surface, hot tears, hard spots and large holes on the outer surface of casting by the operator.

The casting engineer will determine casting based on visual appearance using a magnifying glass and listening to the sound (tone) of casting by tapping casting with a mallet to determine cracks.

Visual testing is of three types:

Direct visual testing.
Translucent visual testing.
Remote visual testing.

Direct Visual Testing

Direct visual testing is done when the sample is 600mm away from the tester and 30° in visual angle.

Tranasulscent Visual Testing

An illuminator is used for translucent testing which consists of directional lighting and artificial lighting. Areas for examination are illuminated by this lighting giving any disbursed result on the sample.

Remote Visual Testing

In remote visual testing visual aids such as cameras, fibre optics, lights, mirrors, telescopes etc are used for testing casting defects by a quality engineer having 20/20 vision.

Casting defects that can be detected using visual inspection are as follows:

The above casting defects are inspected mechanically or optically by the casting engineer after the final casting is taken out.

These casting defects are visually inspected because they appear on the surface of the casting.

Casting defects which do not appear on the surface of the casting and are not visible to the engineer's eyes go through following casting inspection and testing procedure.

Visual inspection is a non-destructive test conducted to determine defects without destroying the casting in the foundry.

Changes in the dimension and accuracy of the casting can occur due to poor sand mould-making process and inadequate accuracy in the pattern during the pattern-making process.

The following care must be taken before testing a casting for visual testing inspection.

The surface of the casting must be properly cleaned.
The inspection room and specimen should be well-illuminated.
Experienced skilled workers should do the inspection process.

Visual Inspection Advantages

The visual testing method is an inexpensive method to test casting defects.
The process of making samples ready for testing requires less preparation.
The time taken for the test is less.
Visual testing tools and equipment are potable.
Using visual testing tools and equipment requires less training.

Visual Inspection Disadvantages

Experienced skilled quality testers are required for inspecting casting.
Only surface-casting defects can be inspected.
A singular defect is difficult to inspect, and defects in clusters are easy to check visually.
The chances of disintegration of the defect are high, especially if casting with scratches and cracks.

Dimensional Inspection (Non-Destructive Technique NDT Method)

What are dimensional inspection and testing techniques used in the casting process?

(b) Dimensional Inspection And Testing of Casting

Dimensions of final casting taken out of the mould must match the casting demanded by the customer to determine this various dimension measuring instruments and gauges are used.

A few gauges used in this process are shown above in diagram (b) which accepts and rejects the casting component based on the passage and blockage of the gauge in the casting sections. Shown above are the plug gauge, feller gauge, thread gauge and snap gauge.

Dimensional Inspection is a non-destructive testing (NDT) method to check dimensional accuracy in the final casting in the casting industry.

To check the dimensional accuracy of the final casting metrological tools and equipment are used for detecting dimensions such as thickness, holes, angles, cavities, surface roughness, height, weight, slope, length, threads and taper.

Various tools such as vernier callipers, micrometres, plugs, bore gauges, wire gauges, snap gauges, wire gauges, vernier callipers, sine bars, r-gauge, micrometres, microcaliper, microscopes, height gauges, scales and rulers, sine bars and bubble gauges are used to determine if the casting dimensions produced match the exact casting dimensions required.

A few of these dimensions measuring instruments have been shown in diagram (c) above which are used to measure length, diameter, thickness of casting and depth of casting section.

Dimensional inspection is done in the metrology department in the foundry.

Dimensional Inspection By CMM (Coordinate Measuring Machines)

Advanced techniques such as CMM (Coordinate Measuring Machines) are used to detect dimensional defects accurately.

CMM can be manual or automated. The probe can be the laser, white light, mechanical or optical taking measuring in six degrees of freedom measuring the physical geometrical characteristics of an object and displaying results on the machine screen.

Surface Finish & Quality Inspection Of Casting (Non-Destructive Technique NDT Method)

Profilometers are used to measure the roughness of the casting.

Surface finish and quality inspection is a non-destructive testing (NDT) method to check surface finish, roughness and quality of the final casting in the casting industry.

Profilomerts gives high peaks and depth of casting surface. Profilometers calculate the difference and give surface roughness results on the screen.

Profilometers are of two types and they are as follows:

Contact profilometers.
Non-Contact profilometers.

Profilometers can be static and portable devices used in foundry giving surface roughness results in nanometers within less time.

Metallurgical Inspection & Control (Destructive Technique DT Method)

What are metallurgical testing, inspection, control and methods used in the casting process?

Mechanical Testing

Casting manufactured in the foundry should meet requirements such as tensile strength, compression strength, yield strength, ductility, hardness, plasticity, fracture, impact resistance, fatigue, stiffness, bending, shear strength, ductility, elasticity, elongation, wear resistance, load-bearing capacity and toughness strength.

(d) Tensile, Shear, Compressive And Bending Test To Check Strength Of Casting Samples

Metallurgical inspection and control is a destructive testing (DT) method to check for casting properties of the final casting.

To meet this requirement casting is made with proper ingot materials keeping in mind to make final defect-free casting which matches the engineering metallurgical specification.

Final casting is subjected to various hardness tests, impact tests, shear strength tests, bending tests, toughness tests, compression and tensile strength tests as shown above in the diagram (d).

A few samples of the casting are selected to determine if the casting is sound or not. This is possible when casting is mass-produced in a casting process such as squeeze casting, continuous casting, centrifugal casting, slush casting and die casting.

Quality engineers note all the measurements, tests and results to come to the conclusion if the manufacturing process should continue or not.

For casting produced from sand casting or any other casting process which does not have any functional value but aesthetic value only, metallurgical inspection, test and controls are skipped.

A metallurgical control test is done on the casting to check shear strength, compressive strength, tensile strength, bending test, hardness test and creep test.

To conduct this test castings are subjected to universal testing machines to check changes in the strength and properties of the casting under shear, compressive, hardness, tensile and bending force.

This testing method is destructive and used where casting samples are checked until their reach and failure point.

Hardness is tested with simple (Brittle Hardness Number) BHN using a small ball of 10mm indenter and load as shown below in diagram (e).

(e) Brittle Hardness Tester To Check Hardness Of Casting

Other tests to determine the hardness of the casting surface are the Rockwell hardness test and the Vicker hardness tester as shown below in diagram (f).

(f) Vickers Hardness Tester To Check Hardness Of Casting

Charpy tests are done to determine energy absorption, ductility and strength.

The tensile test is done to determine the highest ultimate tensile strength of the casting component.

To conduct this test the casting needs to be broken and a sample of the casting needs to be checked making this test a destructive test as compared to non-destructive methods where castings are not cut.

Pressure Test (Non-Destructive Technique NDT Method)

Pressure tests are carried out on casting to determine cracks, openings and leakage in the final pressure vessel casting such as battery and engine housing, piston cylinder, oil pump, engine, valves, engine manifolds, compressor housing, radiator case, rotor housing, stator housing and cylinder head.

Casting is placed in the vessel first and passed through pressurised air, water or oil.

Pressure tests are of two types:

Water-soap test
Air pressure test

Water Test

If there is leakage in the final casting during the water test there is the formation of bubbles which clearly indicates the presence of leakage, cavities, openings and cracks.

Water testing detects tightness and any leakages in the casting sections by immersing the casting in water diluted with soap.

Any presence of positive leakage will show the bubbles rising to the top surface of the soap water solution.

Before the pressure test on casting is done casting holes, flanges and ports are blocked by plugs to avoid false detection of casting.

Air Pressure Test

The pressure test process starts with placing casting in a closed pressurised vessel.

Impregnation Test To Detect Leakage

Impregnation of casting is done to detect any positive leakage in the final casting. Leakage can take place because of "micro-defects" such as cracks, cavities, porosity and holes in the final casting caused by misrun, blowholes, pinhole clusters, improper solidification and cold shunt of casting.

The process starts with the immersion of the casting into a liquid of sodium silicate, oil, water, lacquer, and phenol form and checking any bubbles to detect any cavities in the casting.

Checking leakage of the casting starts by dipping the casting into sodium silicate and creating a vacuum to remove any existing air in the casting cavities.

This sodium silicate solution enters into the cavities of the casting under the pressure of compressed air up to 5 mpa. The operator is present to observe any signs of the bubbles and detect any defects in casting products.

If leakage is negative casting is forwarded further for processing or scrapped if there is any present in the leakage of casting.

Magnetic Particle Inspection And Testing (Non-Destructive Technique NDT Method)

(g) Magnetic Inspection And Testing Method In Casting

Casting defects such as small voids and cracks that are not visible to the engineer's eyes and are below the surface of casting are inspected and tested using magnetic particle inspection as shown above in diagram (g).

Magnetic particle inspection and testing is a non-destructive testing method used in foundry.

Magnetic particle inspection is possible for only casting that is made of ferromagnetic material and has ferromagnetic properties such as nickel, iron, cast iron and cobalt.

The process of checking voids by magnetic particle inspection methods starts with pouring powdered particles on the casting or wetting the casting magnetically and passing a lower voltage, high amperage current which creates a magnetic field creating a flux.

The wet method is more suitable for vertical casting sections and magnetic particles are charged with bars and coils.

The dry method is a cleaner way to do magnetic particle testing compared to the wet method where casting is bathed and dipped into the corrosive liquid fluid.

The dry method uses small fine iron particles with fluorescent coating and checks under the UV rays to see any change in the magnetic particle patterns.

In the dry magnetic particle testing process magnetic particles are sprayed on the surface of the casting.

For the wet method, superflux liquid is used to immerse the casting and check the change in the magnetic field particles.

The casting section to be tested once magnetised is charged will show magnetic pattern lines around the defect such as cracks, porosity and voids.

Casting sections which consist of cracks and voids can be seen with very disturbed magnetic field patterns formed by magnetic powder particles.

Leakage of the magnetic field is clearly visible on the casting surface as there is a discontinuity in the magnetic field boundary.

Magnetic particles will form clusters around casting defects which can be seen with proper lighting.

Galvonomtere indicates changes in the EMF around the coil as the instrument is moved around the casting surface to detect cracks, holes and cavities.

Cavities that are perpendicular to the magnetic field are detectable as compared to the cracks that are parallel to the magnetic field.

Advantages of Magnetic Particle Inspection

The process of magnetic particle inspection is easy.
Skilled trained workers are not required.
Small discontinuity in casting can be easily inspected.
The result of the test is immediate in less time.
The process of checking un-uniformity is quick.

Disadvantages of Magnetic Particle Inspection

Difficult to detect the depth of the casting defect using magnetic particle inspection instruments.
The surface of the casting gets magnetized and needs to be demagnetized after the process.
The surface of the casting should be smooth for better results, the rough surface of the casting does not give the expected result.
Only ferromagnetic casting can be inspected.
Section of the casting must be accessible to the quality inspector and tester.

Dye-Penetration Inspection (Non-Destructive Technique NDT Method)

What is the dye-penetration inspection method used in the casting process?

(h) Dye Penetration Inspection And Testing

Dye penetration inspection is carried out on casting that has casting defects that cannot be detected using the magnetic particle inspection method as shown above in the diagram (h).

Dye penetration inspection is also called liquid penetration inspection and is used to detect small pores and laps in ferrous metals, non-ferrous metals, plastics and ceramics.

The dye penetration testing method can detect small minute surface discontinuities for ferrous and non-ferrous metal casting products.

The principle of this testing method is based on the capillary action where the dye travels to the opening.

There are two types of liquid penetration fluid used in this process first one is visible and fluorescent.

Visible dye penetrants are red and can be easily seen by the naked eye while fluorescent penetrant requires ultraviolet (UV) lights to see green/yellow fluorescence.

The dye penetration inspection and testing method is a non-destructive testing method used in foundry.

Dye Penetration Process Step-By-Step Process Is As Follows:

Step by step dye penetration process is as follows:

Clean the surface of the casting with acetone or degreasing to remove dirt, oil, grease, slag, oxides, welding slag, metal coating and paint.
The casting to be inspected is dipped or sprayed in fluorescent materials and allowed to rest for some time. The liquid used for this is called penetrant which penetrates in the casting.
The casting is then wiped and dried with the remover.
The non-aqueous developer is applied now to the casting surface.
Switch on the light to inspect and see any illumination on the casting surface.
Then casting is inspected to see if any discontinuities on the surface.
Darkness discontinuities on the surface are observed and compared to the previous surface to see any changes on the casting surface to detect casting defects.

Dye Penetration Inspection Process Advantages

The dye penetration process is portable and easy.
Takes less time for inspection.
The process is sensitive to small discontinuities of pores and laps.
Less training in the dye penetration inspection process is required.
The process is inexpensive.

Dye Penetration Inspection Process Disadvantages

Casting depth is not possible to measure using dye penetration inspection.
This is a fully visual inspection process that gives only a visual angle of the defect without any result or internal defects.
Casting surface preparation for the testing is required.
The surface needs to be properly cleaned and then inspected.

Ultrasonic Inspection (Non-Destructive Technique NDT Method)

What is the ultrasonic inspection technique used in the casting process?

(i) Ultrasonic Inspection And Testing To Check Casting

The ultrasonic inspection method is used for casting to detect casting defects in metals having high damping capacity as shown above in diagram (i).

When ultrasonic waves are passed through casting, any change in non-homogeneous sections of casting is detected on the ultrasonic machine.

In this method, it is expected that the beam reflects from the dense surface indicating any cracks, gaps, cavities, voids, porosity, holes or blowholes in the casting surface.

The principle of ultrasonic testing is to use high-frequency sound waves to detect any defects and discontinuities in the ferrous and non-ferrous casting sections such as lead, zinc, and copper.

To conduct this test the surface should be free from all irregularities, dirt, scales, bumps, uneven surfaces and paint.

Ultrasonic waves are generated with the application of piezo-electric effects. Electric energy is applied across the crystal which will cause the crystal to expand or contract and oscillate against the surface of the casting with the help of the coupling fluid.

During the ultrasonic inspection process, sound waves are created and will pass through the casting. These sound waves will reflect back from the discontinuity in the casting and will reach the amplifier and be measured with C.R.O.

These sound waves are passed and received through transducers.

The difference between sound waves of casting with discontinuity vs sound waves of casting without discontinuity is measured as there will be a change in the sound pressures.

Using an ultrasonic detector, the ultrasonic signals are passed and reflected back as eco to see any nonuniformity and defects in the final casting.

If there are any hidden flaws in the casting surfaces made from cast iron the sound waves will travel from the pulse generator and will be reflected back to the source and amplified to see change in the initial pulse and discontinued pulse.

Taking into consideration the time to reach the surface, the time to receive the signal back to the detector and the strength of the signal shows the discontinuity of the casting defect and the location of the defect.

Low-damping materials such as aluminium, lead, and tin are not best for ultrasonic testing.

Ultrasonic testing is a non-destructive testing method to check any voids, holes, cracks, un-uniformity, unevenness and cavities in the casting as equipment can detect changes in the sound wave's shape, amplitude, size, length and depth.

This inspection and testing method finds application in determining welding joints of pump casing components.

Advantages of Ultrasonic Inspection And Testing

The ultrasonic inspection process can be fully automated.
Small to large cavities can be easily determined using the ultrasonic testing method in casting.
Casting sections up to a depth of 10m can be inspected.
Less preparation of the casting surface is required.
The nodular count of ductile iron can be inspected.
Ultrasonic instruments used to detect casting defects are very portable and compact.
The result achieved is very quick and fast.
Compared to radiography inspection ultrasonic inspection method is safe.
Inspection and testing can be done from one side only.
The thickness of casting sections can be easily determined using the ultrasonic technique.
The location, shape and size of the casting defect can be identified.

Disadvantages of Ultrasonic Inspection

The cost of ultrasonic tests is high.
Not suitable for casting with coarse grain structure as the transmission of ultrasonic sound is low,
A skilled operator is required to do the test.
The surface of the casting section should be easily accessible even if only one side of the casting is required for inspection.
Homogeneous casting with even sectional thickness is required.
Ultrasonic inspection cannot be conducted on irregular shape casting.
Ultrasonic equipment must be calibrated frequently.
The surface needs to be smooth, regular, clean and all-time wet to get quality results.

Radiographic Examination (Non-Destructive Technique NDT Method)

What are radiographic examination techniques used in the casting process?

Radiography is an excellent inspection method technique for ferrous and non-ferrous metals to detect casting with internal defects which cannot be detected by visual testing methods.

Radiography examination consists of the use of X-ray and Ɣ-Ray to detect casting defects.

When X-ray machines are used the rays pass through the material. As there are changes in the density and structure of the internal casting because of defects, various shadows are seen on the X-ray image as the density changes.

If there is a clear crack or cavity in the casting more penetration of rays will be observed in that casting area showing a certain change in the shadow on the monitor.

This method is expensive as compared to other inspection methods such as visual inspection, dye penetration inspection and magnetic particle inspection.

X-ray is more scattered as compared to the Ɣ-Ray. Ɣ-Ray from radium is more dense and focused and used to detect defects from thick heavy walls such as cracks, porosity, voids, holes and cavities.

Defects and discontinuities such as cracks, fused cores, shrinkage, porosity, sand particles, pinholes, unfused chills, unfused padding, inclusions, blowholes and unfused chaplet can be easily detected, inspected and explained using the radiography technique.

Radiography examination if the casting is done to determine the following gas casting defects.

Radiographic examination is widely used in bigger foundries to detect gas defects which are below the surface of the casting as density varies if there is a void, cracks or holes.

Radiographic instruments used in the inspection process can be portable and able to conduct inspections for multiple components at the same time.

Advantages Of Radiographic Examination

Internal defects can be easily detected with radiography examination.
Suitable for both ferrous and non-ferrous metal castings.
The result observed on the inspection machine is visual giving a better picture of the casting defect.
Any size and shape of casting can be inspected.
The process for preparing samples is less in the radiographic examination.
Large quantities of casting can be inspected at once.

Disadvantages Of Radiographic Examination

Workers need to be trained to identify the type of casting defects.
Equipment cost is expensive.
Radiography instruments and equipment should be used with standard safety procedures.
The depth of the casting defect is impossible to detect.

Eddy Current Inspection (Non-Destructive Technique NDT Method)

(j) Eddy Current Inspection And Testing To Check Casting

What is Eddy's current inspection testing method?

Eddy's current inspection method is a non-destructive method that consists of passing an electric current through the casting to be inspected for internal defects as shown above in the diagram (j).

This method can detect small flaws and cracks in the final casting observing the difference between the magnetic field generated by the coil when current is passed from the probe.

Eddy's current inspection method is best suited for materials having electrical current properties.

Electric current (AC) is passed through the casting by coil depending upon conductivity, geometry and permeability of casting creating an electric field around the discontinuity to be tested.

This discontinuity present in any form for example crack or void internally in the casting is seen on the eddy current inspection instrument.

Eddy Current Inspection Advantages

The instrument used is compact and portable.
The process of inspection and testing is easy.
Sensitive towards small and minute discontinuities.
Only a little preparation of the surface is required.
The time taken in this process is less.

Eddy Current Inspection Disadvantages

Only internal casting defects can be detected.
Inspection can be done only with a surface of casting that is accessible.
Only material having electrical conductivity can be inspected.
Casting sections with varying hardness will give disturbed signals and can be mispunctuated for cracks.
A trained and skilled inspector is required.
The casting surface should be smooth without any roughness.
Proper interpretation of the casting defects needs to be done by a trained operator having good experience and knowledge.

Casting Repair

Explain the repairing process of casting once the casting is taken out of the mould?

After inspection and testing of casting it becomes necessary to repair the casting made from various casting processes.

Cold Welding

Cold welding is done to fill any small cracks, holes and cavities with filler material such as aluminium, stainless steel, copper and nickel-copper alloy.

Gas welding and electric arc welding (EAW) are used to fill small cavities and by melting this filler material with gas flames or filler rods.

Hot Welding

Hot welding is done for cavities, holes and cracks which are larger in size compared to cracks that are filled using cold welding technique.

To fill the crack defects with the filler rods using electric arc welding and gas welding casting is preheated up to 550℃.

After the casting is heated filer rods are melted and allowed to fill the large gaps, cracks and cavities.

Metal Spraying

Metal spraying consists of spraying molten metal on the defective cracked surface with a metal sprayer filling the cracks and gaps observed on the casting.

Before starting the metal spraying process the casting surface is cleaned with a sandblasting operation to remove any sand.

Casting is pre-heated to 250℃ making the casting surface and finxed to a rotating fixture suitable for spraying metal coating.

Molten metal is sprayed by sparking two wires at the common junction near the nozzle and allowing compressed air to spray the molten metal on the casting surface.

Small drops of molten metal sprayed on the casting solidify quickly covering any defects, imperfections, uniformity, open porosity and cracks.

This method does not cause any distortion, shrinkage in casting, change in dimension and accuracy of thinner sections of casting as compared to the hot welding casting repair method.

Luting And Sealing

Luting and sealing are used to repair the surface of the casting by using epoxy resin as putties and lutes.

The surface of the casting is covered with plastic epoxy resin to smooth the surface of the casting and allow it to solidify creating a strong surface that can be easily machined..

This surface coating is allowed to solidify to remove any imperfections, properly trimmed removing any unwanted edges of resin and made smooth before dispatching it to the customers.

Luting and sealing of the casting is done with synthetic resin, linseed oils, fish oil and wax.

After the cavities, holes, and cracks are repaired impregnation test is done to repair the casting.

Casting Inspection And Testing | Non Destructive Testing (NDT) | Destructive Testing (DT) Method For Casting | Casting Repairing | Mechgrace |