Find the most up-to-date version of IS PART 1 to 3 at Engineering Is Die Steel Forging Standard - Download as PDF File .pdf), IS: (PartsItoIU) Indian Standard ” TOLERANCES FOR CLOSED DIE. Descripción: Is Die Steel Forging Standard. publication of the Bureau of Indian Standards is of particular interest to the public.
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IS(PartsItoIU) Indian Standard. ” TOLERANCES FOR. CLOSED DIE STEEL FORGINGS. (First Revision). Steel Forgings Sectional. IS to 3 - - Tolerances for Closed Die Steel Forgings. Thumbnails 1 homeranking.info IS to 3: Tolerances for Closed Die Steel Forgings. byBureau of Name of Standards Organization: Bureau of Indian Standards (BIS).
For centre-to-centre tolerance from Table 2. In such cases these standard tolerances shall form only a basis on which to agree modifications appropriate to the particular circumstances. Short edges and corners on upset forgings are undesirable features and all fillet and edge radii should. ZS f Part II. They are alternatives for applying length tolerances. Blend of three or more male edge radii form- 2.
Schedules for Wrought Steels, Part 2: Carbon Steels Unalloyed Steels , Section 1: Carbon Steels Unalloyed Steels , Section 2: Carbon Steel Wires with Related Properties.
Schedules for wrought steels, Part 4: Alloy steels Alloy constructional and spring steels with specified chemical composition andd mechanical properties. Schedule for wrought steels, Part 7: Steels for elevated temperature service creep resistant steels. Commentary on Indin Standard Schedules for wrought steels, Part 2: Carbon steels unalloyed steels Complementary to IS Part 2: IS to 3 pdf IS to 3 txt. Rationalized steels for the automobile and Ancillary Industry, Part Technical conditions for the supply of hot rolled billets blooms, slabs and bars for closed die forgings.
Machining allowances and tolerances for open die steel forgings, Part 1: Machining allowances and tolerances for open die steel forgings, Part 2: High alloy steel forgings. Non Magnetic stainless steels for electrical applications, Part 2: Specific requirements for binding wire. Non Magnetic stainless steels for electrical applications, Part 3: Surface depression formed bedding of-scales during forging operation. A forging that is formed to the required shape and size by machined impressions in specially prepared dies which exert three dimensional control on the workpiece.
O o-9 1. H4 to respectively. Table 1. The die becomes over-heated and prematurely soft and the rate of wear is unduly increased.
When draft angles are too small there is a tendency for forgings to stick in the die impression. TABLE 1. Finish allowance refers to the amount of material that is to be machined from the forging to obtain the finished part. Forging dimensions are commonly analyzed independently. Lo 94 5 Continued. Quantities shipped within the limits of overrun and under-run are commonly considered to meet quantity requirements. Tolerances are given in Table 1. E Et Tolerances for heavier or larger forgings are subject to negotiation.
In such cases these standard tolerances shall form only a basis on which to agree modifications appropriate to the particular circumstances. Ejector mark tolerances. Pierced hole tolerances.
This quality should not be specified unless the additional forging cost entailed shall be justified by a consequent saving in overall cost. Residual flash and trimmed flat tolerances. Straightness and flatness tolerances. They are best dealt with by consultation at the design stage and shall be agreed to between the purchaser and the supplier. Mismatch tolerances. Fillet and edge radii tolerances see Table 2. Thickness tolerances. Tolerances for centre-to-centre dimensions. Surface tolerances.
Weight tolerances see Table 1. The standard does not include ranges of special Such requirements usually necessitate supplementary operatolerance.
Burr tolerances see Table 2. TABLE 2. Length and width tolerances are to be applied in directions parallel to the main die parting plane.
All variations. The application of such tolerances should be kept to a minimum and. This should be done to obviate unnecessary minor variations between tolerances. In those instances where the variation is of importance. Mismatch at any position relative to the length or width of a forging may bc calculated as follows: Mismatch tolerances are applied independently of any other tolerances. In measuring mismatch.
Where more restrictive tolerances are required. For that reason measurements should be made at areas of the forging least affected by-die wear. The position of the trimmed flat is measured relative to the theoretical point at which the draft angles meet see Fig. Normally the tolerances for the greatest dimension of length or diameter of the forging shall be applied but. The positive residual flash and negative trimmed flat values permitted are given in Tables 2. Residual flash and trimmed flat tolerances are applied independently of.
ZS f Part II. Variations in trimming may produce either a residual flash or a trimmed flat. The residual flash is measured from the theoretical point at which the draft angles meet to the trimmed edge of the flash.
Tolerances for dimensions of pierced holes shall be taken from Tables 2. In the latter case the tolerances shall be indicated against the appropriate dimension on the forging drawing. The characteristics of the drop forging process require that. Thickness tolerances govern permissible variations in any dimension which crosses the parting line of the dies.
Ejector mark tolerances to.. In the case of forgings having a flange from which projects either a deep hub the height of which is more than 1. Since the general shape of the forging determines the effect of cooling and post-forging manipulation on straightness. The tolerances are determined from Tables 2.
All variations in thickness. The nominal diameter and the location of ejector marks will be indicated to the purchaser on the forging drawing before the commencement of production. Straightness tolerances relate to deviations of surfaces and centre lines from the specified contour as caused primarily by manipulation of the piece in post forging process and. Such special tolerances should be negotiated between the purchaser and the supplier. The height or the depth of an ejector mark.
The total tolerances ermitted are shown in Tables 2. When forging dies incorporate ejectors. Where more restrictive tolerances are required for application to individual dimensions of thickness. For base the tolerances shall be tht same as applicable to shape flat Massive block type forgings with neither length nor width or thickness being predominant Hydraulic pump bodies.
The tolerance for centreto-ccntre dimensions. Table 2. When straightness or flatness tolerances are required this shall be indicated on the agreed forging drawing. Straightness tolerances are applied independently of.
For centre-to-centre tolerance from Table 2. Tolerances for fillet and edge radii shown in Table 2.
Sharp edge and corners on drop forgings are undesirable features and all fillet and edge radii should. An allowance is made for the burr or drag formed during trimming or punching. Tolerances for the! Draft angle tolerances -apply to all draft angles. Surface tolerances relate to depth of scale pits and depth of surface dressing.
For a hole which is pierced through. Instances occur in which the eccentric tolerances for blind holes and bosses are inadequate. The minimum value of the eccentricity shall not be less than 0.
Dimensional checks regarding depth of scale pits or any other point in question On forged surfaces should be made in relation to the machining locations. They apply within the limits stated below unless the purchaser specifies otherwise.
For a boss the height of which is greater than the smallest diameter an eccentricity tolerance of 0. For a hole the depth of which is greater than the greatest diameter. In such cases special tolerances shall be negotiated with the purchaser before the commencement of production.
On forged surfaces which are to be machined subsequently. Unforged stock is that part of a forging which has not been intentionally deformed by the forging process. The permissible increase or decrease in original actual diameter or section of bar stock adjoining such forged pornon is the same as the tolerance applicable to the adjoining forged portion on dimensions at right angles to the polar axis of the unforged stock.
When a forging incorporates a length of unforged stock.. Tolerances for the maximum permissible extent of such distortion 32 c. The weight of the total length in question shall be calculated as if of unforged stock. In such cases it may be arranged by negotiation between the purchaser and the manufacturer that the entire tolerance is shown as a positive one.
An allowance is made for distortion occurring at the end of the unforged stem of a forging due to shearing. There is bound to be certain deviation from the original bar stock diameter of the unforged stock. The maximum permissible decrease in original actual diameter of the unforged bar stock is 1.
Where such negative tolerances cannot be permitted. The deviations arc not to exceed the limits given by the tolcrauces. Tolerance for sheared ends are applied independently of.
General quantity tolerances and recommended Part I. Also the deviations of form do not include scale pits and depth of surface dressing see 2. X The type of steel used shall be determined following categories: Ml - Steel with carbon content as Falling within one of the not more than 0.
LINE A W above 5 percent. W not more of Steel with carbon content above 0. To determine the category in which a steel falls. In such cases the factor S. This special procedure is not applied if larger tolerances will result from use of the normal procedure see Fig.
Ss and S.
The horizontal line is then followed to the right. Reference is made to 4. Reference is first made to the appropriate category in the weight column and the tolerances are read off from the vertical columns headed a and b. This drawing is also the only valid document for tolerances on parts of the forging remaining unmachined. For the purpose of classification. This standard does not include ranges of special toler antes.
Considerations of this nature. In such cases these standard tolerances may form only a basis on which to agree modifications appropriate to the particular circumstances. They are best dealt with by consultation at the design stage and shall be agreed between the purchaser and the manufacturer.
In the case of double-ended upset forgings. If such a forging has either no unformed stock see 4. For the purpose of classification any part of an upset which has been forged or formed prior to the upsetting operation shall be regarded as unforged stock see Fig. Diameter tolerances Tolerances on step dimensions Length tolerances Tolerances for mismatch and eccentricity Tolerances for local deviations from original bar stock diameter Residual flash tolerances Tolerances on internal dimensions including diameters of holes 5.
Fillet and edge radii tolerances Table 2. In those instances where the variation is of importance where there is a large difference in dimensions of diameter. The application of such tolerances should be kept to minimum and.
Straightness and flatness tolerances Tolerances for centre-to-centre dimensions 5. In the case of a symmetrical forgings. For diameters in that part of an upset portion formed in the grip dies the tolerances are those for the maximum dimensions of the given upset portion of the forging see Fig. For internal dimensions the plus and minus signs are reversed. For a given upset portion the tolerances for the greatest dimension shown on the agreed forging drawing from the parting plane to the extremity of that upset portion measured in a direction parallel to the axis of the bar stock.
For external-dimensions the tolerances dispersions are as shown in the table. Length tolerance for unforged stock. Normally in such cases length dimensions are apphed from the in?
In the case of a forging having a separate upset portion at each end.