Fatigue failure, Flaking, Flowing, Foreign material, Forging marks, Fusion line, Fusion zone, Galling, Glazing

Tabel 2.1 i

DEFFECT	DESCRIPTION
Fatigue failure	Progressive yielding of one or more local areas of weakness such as tool marks, sharp indentation, minute cracks, or inclusions, under repeated stress. As working stress on piece is repeated, cracks develope, at ends of which there are high concentrations of stress. Cracks spread, usually from the surface or near surface, of the area. After a time, there is so little sound metal left the normal stress is higher than strength of remaining material, and it snaps. Failure is not due to crystallization of metal, as many believe. Appearance of a typical fatigue failure is easily explained. As failure proceeds, severed surfaces rubs and batter each other, crushing grains of material and producing full or smooth appearance, remaining unfractured portion preserves normal grain structure up to moment of failure. The progressive nature of the failure is usually indicated by several more or less concentric lines, the center or focus, of which discloses original point or line of failure. • Usual causes are tool marks, sharp corners, nicks, cracks, inclusions, galling, corrosions, or insufficient tightening of studs or bolts to obtain proper stretch.
Flaking	Breaking away of pieces of flated or painted surface. • Usual causes are incomplete bonding, excessive loading, or blistering.
Flowing	Spreading of a plated or painted surface. Usually accompanied by flaking. • Usual causes are incomplete bonding, excessive loading or blistering.
Foreign material	Any solid or liquid material not integral to a part. Such material may or may not be adherent to a surface or passage.
Forging marks	Ridges or grooves on the external surface of a part caused by foreign unwanted material or irregularities on the forming die.
Fusion line	Interface of the weld bead and parent metal.
Fusion zone	The weld bead formed by the melting of filler metal and parent metal, or of parent metal only.
Galling	A transfer of metal from one surface to the other of closely fetted surfaces causing damage to both surfaces. • Usual cause is severe chafing or fretting action caused during engine operation by a slight relative movement on two surfaces under high contact pressure.
Glazing	Development of a hard glossy surface on bearing surfaces. An often beneficial condition except on inner and outer races. • Usual cause is a combination of pressure, oil and heat.

Discontinuity, Distortion, Draw mark, Dross, Electrolytic action, Erosion, Excess braze, Fatigue, Fatigue crack

Tabel 2.1 h

DEFFECT	DESCRIPTION
Discontinuity	Is an interruption in the normal physical structure or configuration of a part such as cracks, laps, folds, seams, porosity, etc. A discontinuity may or may not affects the quality of the part.
Distortion	Extensive deformation of the original contour of apart Usual cause is impact of an unwanted object, structural stresses, or excessive localized heating.
Draw mark	Linear, trough-like grooves which result from the action of die imperfections or foreign material on the drawn material
Dross	Linear imperfection or imperfections in the form of the branching or irregular patterns, caused by impurities or oxides in a cast material.
Electrolytic action	Breakdown of surfaces by electrical action between parts made of dissimilar metals. Usual cause is galvanic action between dissimilar metals.
Erosion	Carrying away of material by flow of hot gases, grit, or chemicals. Usual causes are flow of corroding liquids, hot gases, or dirt-laden oil.
Excess braze	Braze material beyond the joint fillet. Sometimes refered to as a run, streak or flash.
Fatigue	The progressive fracture of a material under circled stress loading.
Fatigue crack	Occurs only in parts that have been in service under repeated stress reversals or stress variations. The crack starts at a highly stress area and propagates through the section until failure occurs. A fatigue crack will start more readily where the design or surface condition provides a point of stress concentration, such as fillets, poor surface finish, seams, grinding cracks, and from fastener holes that have poor surface finish and sharp burrs.

Crack, Crater, Crazing, Creep, Deformation, Delimitation, Dent, Deviation, Depressed Imperfection

Tabel 2.1 g

DEFFECT	DESCRIPTION
Crack	A partial fracture. Linear imperfection in the form of a narrow break or fissure. Usual cause is excessive stress due to sudden overloading, extension of a nick or scratch, or overheating.
Crater	A depression at the termination of a weld bead.
Crazing	A network of minute cracks appearing in the coating of coated parts.
Creep	Gradual continuous distortion or plastic flow under constant stresses.
Deformation	Any alteration or change of shape, diminution, or configuration resulting from stress or damage.
Delimitation	A separation of the layers in a layered material.
Dent	Small smoothly rounded hollow in the surface. Usual causes are concentrated overloading resulting from peening, or presence of chips between loaded surfaces, or the striking of a part.
Deviation	Any condition that causes a part to differ from the manufacturer’s blueprint.
Depressed Imperfection	One that is below the general surface of the part, may have either smooth or irregular sharp edges or bottom

Chipping or chip, Corrosion, Surface Corrosion, Dissimilar metal corrosion, Stress corrosion, Fretting corrosion

Tabel 2.1 f

DEFFECT	DESCRIPTION
Chipping or chip	Breaking out of small pieces of metal which have been removed mechanically. Usual cause is a concentration of stress due to nick, scratches, inclusions, peening, or careless handling of parts. Do not confuse with flaking.
Corrosion	Metal corrosion is the deterioration of the metal by chemical or electrochemical attack, water of water vapor containing salt combined with oxygen in the atmosphere produce the main source of corrosion in engines. Engines operating near the sea or in areas where the atmosphere contains industrial fumes which are corrosive are susceptible to corrosion attack. Corrosion may change the smooth surface, weaken the interior or damage and lossen adjacent parts. In some cases treatment of parts especially ligh alloys take place by corrosion caused by fabrication. An electrochemical attach may be linked chemically to the electrolytic reaction which takes place in electroplating, anodizing, etc
Surface Corrosion	Appears as a general roughness, or pitting of the surface of the metal. Sometimes corrosion will spread under the surface coating and cannot be recognized either by roughening of the surface or the powder deposit (rust). In case like this, the paint or plating will be lifted off in surface in small blisters which results from the pressure of the underlying accumulation of corrosion products.
Dissimilar metal corrosion	Excessive pitting damage may result from contact between dissimilar metal parts in presence of a conductor. While suface corrosion may or may not take place, a galvanic action not unlike electroplating occurs at the point of areas of contact where the insulation has broken down or being omitted. This electrochemical attach can be serious because the action is, in many instances, taking place out of sight and the only way to detect it is by disassembly and inspection.
Stress corrosion	Stress corrosion occurs as a result of the combined effect of sustained tensile stresses and corrosive environment. Stress corrosion cracking is found in most metal systems especially of aluminum, copper, certain stainless steels and high srtength alloy steels. Aluminum alloy parts with pressed in bushings, clevis, pin, joints, shrink fits and overstressed nut are examples of parts which are suscestible to stress corrosion cracks.
Fretting corrosion	Is a form of corrosion attach which occurs when two matting surfaces, normally at rest with respect to one another are subject to a slightly relative motion. It is characterized by pitting on the surfaces and the generation of considerable quantities of finely devited debris. Since the restricted movements of the two surfaces prevent the debris from escaping, an localized abrasion is occurs. The presence of water vapor increases this type of deterioration.

Burst, Chain Porosity, Chafing, Chatter Marks, Clearly separated, Cluster, Cold Shut

Tabel 2.1 e

DEFFECT	DESCRIPTION
Burst	Crack caused by rupture extending out ward for a central point.
Chain Porosity	Porosity in linear alignment.
Chafing	A rubbing action between parts having limited relative motion. To be interpreted as an action which produces a surface condition rather than as a description of a damage. See also “gall” or “scratch”.
Chatter Marks	Waves or ripples on a machined surface, in the direction of the cut. Caused by a loose or dull cutting tool, or a tool that is not rigidly supported.
Clearly separated	Imperfections which are not touching when viewed with the unaided eye
Cluster	Two or more imperfections, clearly separated which can be contained within a circle of the maximum diameter allowed circle shall be counted as one imperfection
Cold Shut	Intermittent of continuous lines caused by unfused material.

Burn, Burn Out, Burning, Burnish, Burnishing, Burr

Tabel 2.1 d

DEFFECT	DESCRIPTION
Burn	A rapid, destructive, oxidizing action. Change in color appearance often indicates this condition. Usually caused by higher temperature than the parent material can withstand
Burn Out	Electrochemical machining erosion beyond the desired feature profile
burning	Damage to part by excessive heat. Evidenced by characteristic discoloration or in severe cases, by a loss or flow of material. Usual causes are excessive heat due to lack of lubrication, improper clearance, or abnormal flame pattern
Burnish	Shiny area resulting from rubbing against a hard smooth surfaces, may contain scratches of no apparent depth.
Burnishing	Mechanical smoothing of a metal surface by rubbing. Not accomplished by removal of material but sometimes by discoloration around outer edges of area. Operation burnishing is not detrimental if it covers approximately the area carrying the load, and if there is no evidence of pile-up or burning. Usual cause is normal operation of parts.
Burr	A sharp projection or rough edge Usual cause is excessive wear, peening, or machining operations.

Break, Brinelling, Brittle, Buckle, Bulge, and Burn Marks

Tabel 2.1 c

DEFFECT	DESCRIPTION
Break	Complete separation by force into two or more pieces. Usual causes are fatique or sudden overload
Brinelling	Indentations some times found on the surface of ball or roller bearing parts. Usual cause are improper assembly or dissasembly techniques by the aplication of force on the free race. Bearing which do not have full, constant rotation and are subject to sudden loading, have brinelling tendencies.
Brittle	A large scale deformation of the original contour of the part. Usually caused by aging, extreme cold, chemical action, or cold working
Buckle	A large scale deformation of the original contour of the part. Usually caused by pressure or impact from a foreign object, structural stresses, excessive localized heating, high pressure differentials, or any other combination of these
Bulge	An outward bending or swelling. Usual cause is excessive pressure or weekening due to excessive heat.
Burn marks	Localized indication of excessive heating (for example, blue to blue blackdiscoloration) due to excessive dwell time of a tool at that location, or electrical arcing due to improper contact between an electrode and the part.