IS 1786: 2008 Steel Bars with Latest Amendment & Updated code for Steel Bar
IS 1786: 2008 Steel Bars with Latest Amendment & Updated code for Steel Bar
1. Sariye ke Grades (Strength Grades)
Amendment No. 3 ke baad ab standard mein ye grades shamil hain [A3, Clause 1.1, Page 1]:
Fe 415, Fe 415D, Fe 415S
Fe 500, Fe 500D, Fe 500S
Fe 550, Fe 550D
Fe 600, Fe 650, Fe 700
D aur S ka matlab:
'D' (Ductile): Iska yield stress wahi rehta hai lekin elongation (lachilapan) zyada hota hai.
'S' (Super Ductile): Ye grade seismic (bhookamp) areas ke liye special requirements ke saath aata hai.
Strength (Takat)
Yield Stress (Min): Fe 415/D/S ke liye $415.0\text{ N/mm}^2$ aur Fe 700 ke liye $700.0\text{ N/mm}^2$ hai.
Yield Stress (Max): Fe 415S ke liye max limit $540.0\text{ N/mm}^2$ aur Fe 500S ke liye $650.0\text{ N/mm}^2$ fix ki gayi hai.
2. Chemical Composition (Ladle Analysis)
Amendment No. 3 ke hisab se ladle analysis ki nayi limits [A3, Clause 4.2, Page 1]:
| Constituent (%) | Fe 415S | Fe 500S | Fe 650 | Fe 700 |
| Carbon (C) | 0.25 | 0.25 | 0.32 | 0.32 |
| Sulphur (S) | 0.040 | 0.040 | 0.040 | 0.040 |
| Phosphorus (P) | 0.040 | 0.040 | 0.040 | 0.040 |
| S+P (Total) | 0.075 | 0.075 | 0.075 | 0.075 |
Carbon Equivalent (CE): Fe 415S/500S ke liye CE max 0.50%
aur Fe 700 ke liye max 0.61% hai. - Nitrogen Content: Max 0.012% (120 ppm) hona chahiye. Agar nitrogen binding elements (Nb, V, Ti, Al) sahi matra mein hain, toh 0.025% (250 ppm) tak allow hai.
3. Nominal Sizes (Sariye ka Size)
Amendment No. 1 ke hisab se sizes mein 45mm aur 50mm wapas jod diye gaye hain [A1, Clause 6.1, Page 3]:
Standard Sizes: 4, 5, 6, 8, 10, 12, 16, 20, 25, 28, 32, 36, 40, 45, 50 mm.
Nominal Mass aur Area (Table 1 updates) [A1, Page 3]:
45 mm: Area = $1591.1\text{ mm}^2$, Mass = 12.49 kg/m.
50 mm: Area = $1964.4\text{ mm}^2$, Mass = 15.42 kg/m.
4. Weight aur Tolerance
Tolerance limits wahi hain jo main code mein thi, lekin Amendment No. 4 ne tensile aur bend test ke references update kiye hain [A4, Page 1]:
Tensile Test Reference: Ab IS 1608 (Part 1): 2018 follow hota hai
. - Bend Test Reference: Ab IS 1599: 2012 follow hota hai.
5. Mechanical Properties (Test Results) [A3, Table 3, Page 2]
| Property | Fe 415S | Fe 500S | Fe 650 | Fe 700 |
| TS/YS Ratio | $\ge 1.25$ | $\ge 1.25$ | $\ge 1.06$ | $\ge 1.06$ |
| Elongation (%) | 20.0% | 18.0% | 10.0% | 10.0% |
| Total Elongation at Max Force (%) | 10% | 8% | N/A | N/A |
Bend aur Rebend Test [A3, Table 4, Page 2]:
Bend Test (Up to 20mm): Fe 415S/500S ke liye mandrel dia $2\phi$ aur $3\phi$ hai. Fe 700 ke liye ye $7\phi$ hai.
Rebend Test (Up to 10mm): Fe 415S/500S ke liye mandrel dia $4\phi$. Fe 700 ke liye ye $7\phi$ hai.
6. TMT Process aur Marking
BIS Certification: Ab Bureau of Indian Standards Act, 2016 ke assessment schemes ke hisab se marking hoti hai [A4, Clause 13.4, Page 2].
Dispute Note: Agar tensile test results mein koi vivaad (dispute) hota hai, toh full bar test (bina machining ke) ka result hi final mana jayega [A1, Clause 9.1.2.1 Note, Page 3].
IS 1786: 2008 Steel Bars High strength deformed steel bars for concrete.
1. Sariye ke Grades (Strength Grades)
IS 1786: 2008 ke mutabik, ab ye grades hote hain [Clause 1.1, Page 3]:
Fe 415, Fe 415D [Clause 1.1 (a), Page 3]
Fe 500, Fe 500D [Clause 1.1 (b), Page 3]
Fe 550, Fe 550D [Clause 1.1 (c), Page 3]
D ka matlab: Jis grade ke peeche 'D' laga hai, uska yield stress to wahi rahega lekin uska elongation (lachilapan) zyada hoga [Clause 1.1 Note 2, Page 3].
Strength (Takat)
Dono ka yield stress (jis point par sariya khichna shuru hota hai) ek barabar hota hai:
Yield Stress (Min): Dono ke liye $415.0\text{ N/mm}^2$ hai [Table 3, Page 8].
Ductility aur Elongation (Lachilapan)
Yahan asli farak aata hai. 'D' ka matlab hi Ductility hai:
Fe 415: Isme minimum elongation 14.5% honi chahiye [Table 3 (ii), Page 8].
Fe 415D: Isme lachilapan zyada hota hai, isliye iska minimum elongation 18.0% rakha gaya hai [Table 3 (ii), Page 8].
Total Elongation at Max Force: Fe 415D ke liye ye kam se kam 5% hona zaruri hai, jabki normal Fe 415 ke liye iska koi fixed rule nahi diya gaya [Table 3 (iv), Page 8].
Chemical Composition (Milawat)
'D' grade wale sariye ko zyada pure (shuddh) rakha jata hai taaki wo asani se mude:
Carbon (C): Fe 415 mein max 0.30% chalta hai, lekin Fe 415D mein sirf 0.25% tak hi allow hai [Table Clause 3.10/4.2, Page 4].
Sulphur (S) aur Phosphorus (P):
Fe 415 ke liye max limit 0.060% hai [Table Clause 3.10/4.2, Page 4].
Fe 415D ke liye in impurities ko kam karke 0.045% kar diya gaya hai [Table Clause 3.10/4.2, Page 4].
Tensile Strength (Khenchne ki Takat)
Fe 415: Iski tensile strength yield stress se kam se kam 10% zyada honi chahiye (lekin kam se kam $485.0\text{ N/mm}^2$) [Table 3 (iii), Page 8].
Fe 415D: Iski tensile strength yield stress se kam se kam 12% zyada honi chahiye (lekin kam se kam $500.0\text{ N/mm}^2$) [Table 3 (iii), Page 8].
Bend Test (Site Check)
Site par jab sariya modte hain (Mandrel ke upar), to Fe 415D thoda zyada "safety" deta hai:
20mm tak ka sariya: Dono ke liye mandrel diameter $3\phi$ ($\phi$ = sariye ka dia) hota hai [Table 4, Page 9].
20mm se upar: Fe 415 ke liye $4\phi$ mandrel lagta hai, lekin Fe 415D itna lachila hai ki wo $3\phi$ par bhi bina tute mud jata hai [Table 4, Page 9].
Seedhi baat: Fe 415D zyada safe hai, khaas karke earthquake prone areas mein, kyunki ye zyada mude bina tootte nahi hai.
2. Chemical Composition (Ladle Analysis)
Report check karte waqt dhyan rakhein ki inki matra maximum limit se zyada na ho [Clause 4.2, Page 4]:
Carbon (C): Fe 415/500/550 ke liye max 0.30%, lekin 'D' grades ke liye sirf 0.25% [Table, Page 4].
Sulphur (S): Grades ke hisab se 0.040% se 0.060% tak [Table, Page 4].
Phosphorus (P): 0.040% se 0.060% tak [Table, Page 4].
Chemical Composition (Ladle Analysis) - Max Limits [Table, Page 4]
| Constituent (%) | Fe 415 | Fe 415D | Fe 500 | Fe 500D | Fe 550 | Fe 550D | Fe 600 |
| Carbon (C) | 0.30 | 0.25 | 0.30 | 0.25 | 0.30 | 0.25 | 0.30 |
| Sulphur (S) | 0.060 | 0.045 | 0.055 | 0.040 | 0.055 | 0.040 | 0.040 |
| Phosphorus (P) | 0.060 | 0.045 | 0.055 | 0.040 | 0.050 | 0.040 | 0.040 |
| S+P (Total) | 0.110 | 0.085 | 0.105 | 0.075 | 0.100 | 0.075 | 0.075 |
Carbon Equivalent (CE): Agar weldability guarantee chahiye, toh CE 0.53% se zyada nahi hona chahiye jab microalloys use ho rahe hon. Agar microalloys use nahi ho rahe, toh ye limit 0.42% hai [Clause 4.2 Note 1, Page 4].
Microalloying Elements: Strengthening elements jaise Nb, V, B aur Ti ka total mix 0.30% se zyada nahi hona chahiye [Clause 4.2 Note 2, Page 4].
Nitrogen Content: Steel mein nitrogen ki maatra 0.012% se zyada nahi honi chahiye [Clause 4.2 Note 4, Page 5].
Product Analysis Variation: Agar aap finished product ka test karte hain (ladle analysis ki jagah), toh thodi extra chhoot milti hai [Clause 4.2.1 Table, Page 5]:
Carbon: +0.02% extra.
Sulphur & Phosphorus: +0.005% extra.
3. Nominal Sizes (Sariye ka Size)
Code ne sizes ko thoda badla hai. Ab standard sizes ye hain [Clause 6.1, Page 6]:
4, 5, 6, 8, 10, 12, 16, 20, 25, 28, 32, 36, aur 40 mm.
Note: 7, 18, 22, 45, aur 50 mm wale sizes ab hata diye gaye hain [Foreword (d), Page 2].
IS 1786: 2008 ke mutabik standard sizes ye hain [Clause 6.1, Page 6]:
Small sizes: 4 mm, 5 mm, 6 mm.
Medium sizes: 8 mm, 10 mm, 12 mm, 16 mm.
Large sizes: 20 mm, 25 mm, 28 mm, 32 mm, 36 mm, 40 mm.
Note: Agar manufacturer aur purchaser ke beech agreement ho, to dusre sizes bhi supply kiye ja sakte hain [Clause 6.1 Note, Page 6].
Nominal Mass aur Area (Table 1) [Page 7]
Site par sariye ka wazan (mass) check karne ke liye ye table sabse zaruri hai:
| Nominal Size (mm) | Cross-Sectional Area (mm2) | Mass per Metre (kg) |
| 8 | 50.3 | 0.395 |
| 10 | 78.6 | 0.617 |
| 12 | 113.1 | 0.888 |
| 16 | 201.2 | 1.58 |
| 20 | 314.3 | 2.47 |
| 25 | 491.1 | 3.85 |
| 32 | 804.6 | 6.31 |
Calculations ke liye Zaruri Jaankari:
Density: Steel ki density 0.007 85 $kg/mm^2$ (per meter length) mani jati hai [Clause 85/239, Page 4/7].
Effective Area: Deformed bars ka cross-sectional area unke mass ke hisab se nikala jata hai, asli round bar ki tarah [Clause 6.3.1, Page 7].
4. Weight aur Tolerance (Sabse zaruri)
Ek meter sariye ka standard weight (kg/m) aur usme kitni chhoot (tolerance) milti hai:
Standard Weight: 8mm = 0.395, 10mm = 0.617, 12mm = 0.888, 16mm = 1.58 [Table 1, Page 7].
Tolerance (Batch wise) [Table 2, Page 7]:
10mm tak: +/- 7%
10mm se 16mm tak: +/- 5%
16mm se upar: +/- 3%
Tolerance on Nominal Mass (Table 2) [Page 7]
| Nominal Size (mm) | Batch Tolerance (%) | Individual Sample (%) | Individual Sample (Coils) (%) |
| Up to 10 mm | $\pm 7$ | $\pm 8$ | $-8$ |
| 12 mm to 16 mm | $\pm 5$ | $\pm 6$ | $-6$ |
| 16 mm se upar | $\pm 3$ | $\pm 4$ | $-4$ |
Yaad rakhne wali zaruri baatein (Site Tips):
Individual Sample: Jab aap site par kisi sariye ka ek tukda (kam se kam 0.5 meter) kaat kar uska wazan check karte hain, toh use "Individual Sample" mana jata hai [Clause 7.2.3.1, Page 7].
Batch: Jab poori gaadi ka ya ek saath aaye huye lot ka wazan check hota hai, toh "Batch Tolerance" dekhi jati hai [Clause 7.2.3.2, Page 7].
Individual Sample (Plus Tolerance): Code kehta hai ki individual sample ke liye "plus tolerance" specify nahi hai, matlab sariya thoda bhari ho sakta hai par halka hone ki limit fix hai [Table 2 Note, Page 7].
5. Mechanical Properties (Test Results) [Table 3, Page 8]
0.2 Percent Proof Stress / Yield Stress (Min)
Ye wo takat hai jis par sariya bina tute khichna (deform hona) shuru kar deta hai:
Fe 415 aur Fe 415D: $415.0\text{ N/mm}^2$.
Fe 500 aur Fe 500D: $500.0\text{ N/mm}^2$.
Fe 550 aur Fe 550D: $550.0\text{ N/mm}^2$.
Fe 600: $600.0\text{ N/mm}^2$.
Tensile Strength (Min) [Table 3 (iii), Page 8]
Fe 415: Actual yield stress se 10% zyada (lekin kam se kam $485.0\text{ N/mm}^2$).
Fe 415D: Actual yield stress se 12% zyada (lekin kam se kam $500.0\text{ N/mm}^2$).
Fe 500: Actual yield stress se 8% zyada (lekin kam se kam $545.0\text{ N/mm}^2$).
Fe 500D: Actual yield stress se 10% zyada (lekin kam se kam $565.0\text{ N/mm}^2$).
Fe 600: Actual yield stress se 6% zyada (lekin kam se kam $660.0\text{ N/mm}^2$).
Elongation (Lachilapan) - Min Percentage [Table 3 (ii), Page 8]
Fe 415: 14.5%.
Fe 415D: 18.0%.
Fe 500: 12.0%.
Fe 500D: 16.0%.
Fe 550: 10.0%.
Fe 600: 10.0%.
Total Elongation at Maximum Force (Min)
Ye ek naya parameter hai jo sirf 'D' grades aur Fe 600 ke liye check kiya jata hai:
Fe 415D, Fe 500D, Fe 550D: Kam se kam 5% hona chahiye [Table 3 (iv), Page 8].
Testing Method (Zaruri Jankari)
Tensile Test: Ye IS 1608 ke hisab se kiya jata hai [Clause 9.2, Page 9].
Full Section: Test hamesha poore sariye ke section par hona chahiye, uski size machining karke kam nahi karni chahiye [Clause 9.1.2, Page 8].
Area for Calculation: Stress nikalne ke liye hamesha Effective Cross-Sectional Area ka hi use karte hain [Clause 9.2.2, Page 9].
Note: site par jab sariye ki MTC (Mill Test Certificate) aaye, toh bas Table 3 se ye values mila lena.
Bend aur Rebend Test
Bend Test: Sariye ko mandrel par modne par koi crack ya toot (rupture) nahi dikhni chahiye [Clause 9.3, Page 9].
Rebend Test: Pehle 135° pe modo, phir 100°C garam paani mein 30 minute rakho, phir 157.5° tak wapas modo [Clause 9.4, Page 9].
6. TMT Process (Field Test) [Annex A, Page 12]
Agar check karna ho ki sariya TMT hai ya nahi, to ek chhota tukda kaat kar usse Nital (5% Nitric Acid) se saaf karein. TMT sariye mein bahar ek dark ring (Martensite) dikhegi aur andar halka rang (Ferrite-Pearlite) dikhega.
Nital is a metallographic etching reagent commonly used for revealing microstructure in carbon steels, tool steels, and hardened steels.
Composition (5% Nital): Typical formulation: 5 mL nitric acid ($HNO_3$) and 95 mL ethanol or methanol.
Field Test (Identification Test) Kyun Zaruri Hai?
Kyunki TMT sariya aur Mild Steel (MS) sariya dekhne mein ek jaise lag sakte hain, isliye ye test unke andar ka microstructure check karne ke liye kiya jata hai [Clause A-1, Page 12].
Test ka Step-by-Step Tarika [Clause A-1, Page 12]:
Cutting: Sariye ka ek chhota sa tukda (lagbhag 12 mm lamba) kaat lijiye.
Grinding: Uske katne wale hisse (transverse face) ko ek dum flat ghis lijiye. Iske liye '0' size tak ke fine emery papers (regmar) ka use karein.
Etching: Ab us saaf hisse par Nital (5 percent nitric acid alcohol mein mila hua) lagaiye.
Observation: Kuch seconds ke liye use waisa hi chhodein aur phir dhyaan se dekhein.
Result: Kya Dikhna Chahiye? [Clause A-1, Page 12]
Jab aap nital lagayenge, toh sariye ke cross-section mein do alag hisse dikhne chahiye:
Outer Ring (Anular Region): Bahar ki taraf ek dark (gehra) rang ka ghera dikhega. Ye 'Martensite' ya 'Bainite' structure hota hai jo sariye ko takat deta hai.
Inner Core: Beech ka hissa light (halka) rang ka dikhega. Ye 'Ferrite-Pearlite' core hota hai jo sariye ko lachila (ductile) banata hai.
TMT Process Kaise Kaam Karta Hai? [Clause A-1, Page 12]
Quenching: Garam sariye ko (lagbhag $950^{\circ}C$) pani se tezi se thanda kiya jata hai, jisse bahar ki layer Martensite ban jati hai.
Self-Tempering: Sariye ke beech ki garmi bahar ki taraf aati hai, jisse wo bahari layer 'tempered martensite' ban jati hai, jo majboot bhi hoti hai aur lachili bhi.
Zaruri Baat: Code kehta hai ki ye test sirf pehchan ke liye hai. Agar sariya chemical aur physical properties mein pass hai, toh use accept kiya jayega, bhale hi ye field test kaisa bhi ho [Clause A-1, Page 12].
Frequently Asked Questions (FAQs) - IS 1786: 2008
1. Sariye ke Grades aur Ductility se jude sawal
Q: IS 1786: 2008 ke naye amendments ke baad ab kaun-kaun se naye grades shamil huye hain?
Ans: Naye amendments ke baad ab Fe 415S, Fe 500S, Fe 650 aur Fe 700 jaise naye grades shamil ho gaye hain
.
Q: IS ke anusar Sariye ke grade mein 'D' aur 'S' ka kya matlab hota hai?
Ans: 'D' ka matlab Ductile hota hai (jiska yield stress wahi rehta hai lekin elongation zyada hoti hai)
, aur 'S' ka matlab Super Ductile hota hai, jo bhookamp (seismic) areas ke liye banaya gaya hai .
Q: IS ke anusar Fe 500 aur Fe 500S ke Yield Stress mein kya farak hai?
Ans: Dono ka minimum Yield Stress $500.0\text{ N/mm}^2$ hota hai
, lekin Fe 500S ke liye maximum Yield Stress ki limit $650.0\text{ N/mm}^2$ fix ki gayi hai .
2. Chemical Composition aur Quality se jude sawal
Q: Kya 'D' grade sariye mein Carbon ki matra normal sariye se kam hoti hai?
Ans: Haan, Fe 415/500/550 mein Carbon max 0.30% hota hai, jabki 'D' grades mein ye sirf 0.25% tak allow hai
.
Q: Carbon Equivalent (CE) ki limit kya honi chahiye?
Ans: Weldability ke liye CE max 0.53% honi chahiye jab micro-alloys use ho rahe hon, aur bina micro-alloys ke ye limit 0.42% hai
.
Q: Sariye mein Nitrogen ki matra kitni honi chahiye?
Ans: Normal taur par Nitrogen max 0.012% (120 ppm) hona chahiye
, lekin agar Nb, V, Ti jaise elements sahi matra mein hain, toh ye 0.025% (250 ppm) tak ho sakta hai .
3. Weight, Size aur Tolerance se jude sawal
Q: Amendment No. 1 ke baad kaun se bade sizes wapas jode gaye hain?
Ans: Amendment No. 1 ke hisab se 45mm aur 50mm ke sizes ko wapas standard list mein jod diya gaya hai
.
Q: 10mm se 16mm tak ke sariye ke liye batch weight mein kitni tolerance milti hai?
Ans: 12mm se 16mm tak ke sariye ke liye batch weight tolerance $\pm 5\%$ hoti hai
.
Q: Sariye ka unit weight nikalne ka standard formula kya hai?
Ans: Standard formula $D^2 / 162$ hai
, jisme steel ki density $0.00785\text{ kg/mm}^2$ per meter mani jati hai .
4. Site Testing aur TMT Process se jude sawal
Q: TMT sariye ki pehchan ke liye site par kaun sa field test kiya jata hai?
Ans: Site par Etching Test (Nital solution ka upyog karke) kiya jata hai
, jisme TMT sariye mein bahar ek dark ring (Martensite) aur andar halka core (Ferrite-Pearlite) dikhta hai .
Q: Agar Tensile Test result mein dispute (vivaad) ho, toh kaun sa result final mana jata hai?
Ans: Aise mamle mein Full Bar Test (bina machining ke) ka result hi final aur binding mana jayega
.
Q: IS ke anusar Rebend test mein sariye ko kitne degree par moda aur seedha kiya jata hai?
Ans: Pehle sariye ko 135° par moda jata hai aur phir boiling water treatment ke baad use 157.5° tak wapas moda jata hai
.
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