How to go about Bending this God forsaken 316l chainplate

[Caliber40]

My welding expert with metalurgical training says no problem heating 316L cherry red......Mapp gas is hotter than acetylene and is better for heating but I dont know how big that Mapp Gas torch head is so the acetylene torch may be better....again depends on tip and tank size.

Hope this helps

G

[artisanmach]

FYI. info on 316ss
read the very last comment...cold work, just form it...

Stainless Steel - Grade 316
Grade 316 / 316L Technical Data
Summary
Grade 316 is an improved version of CS 304, with the addition of molybdenum and a slightly higher nickel content. The resultant composition of CS 316 gives the steel much increased corrosion resistance in many aggressive environments. The molybdenum makes the steel more resistant to pitting and crevice corrosion in chloride-contaminated media, sea water and acetic acid vapours. The lower rate of general corrosion in mildly corrosive environments gives the steel good atmospheric corrosion resistance in polluted marine atmospheres.
CS 316 offers higher strength and better creep resistance at higher temperatures than CS 304. CS 316 also possesses excellent mechanical and corrosion properties at sub-zero temperatures. When there is a danger of corrosion in the heat-affected zones of weldments, the low-carbon variety CS 316L should be used. CS 316 Ti, the titanium-stabilised version, is used for its resistance to sensitization during prolonged exposure in the 550oC-800oC temperature range.

Typical Applications

Because of its superior corrosion and oxidation resistance, good mechanical properties and fabricability, CS 316 has applications in many sectors of industry. Some of these include:
Tanks and storage vessels for corrosive liquids.
Specialised process equipment in the chemical, food, paper, mining, pharmaceutical and petroleum industries.
Architectural applications in highly corrosive environments.

Chemical Composition (ASTM A 240)
SX316
SX316L
SX316Ti
C
0.08 max
0.03 max
0.08 max
Mn
2.0
max
P
0.045
max
S
0.030
max
Si
1.0
max
Cr
16.0 to
18.0
Ni
10.0 to
14.0
Mo
2.00 to
3.00
Ti
0.5 max
5X%C
Typical properties in the annealed condition
The properties quoted in this publication are typical of mill products and unless indicated must not be regarded as guaranteed minimum values for specification purposes.

1. Mechanical properties at room temperature
Tensile Strength, MPa
Proof Strength, (Offset 0.2%), MPa
Elongation (Percent in L = 5.65 S0)
Hardness (Brinell)
Erichsen Cup Test Value mm
Endurance (fatigue) limit, MPA
SX316
TypicalMinimum
580515
310205
5540
165-
8 - 10-
260-
SX316L
TypicalMinimum
590485
310170
6040
170-
240-
260-
SX316Ti
TypicalMinimum
600515
320205
5040
165-
--
260-
2. Properties at elevated temperatures
The values given refer to CS 316 and CS 316 Ti only as strength values for CS 316L fall rapidly above 425oC.

Short Time Elevated Temperature Tensile Strength

Temperature, °C
Strength, MPa
600
460
700
320
800
190
900
120
1000
70
Creep data
Stress for a creep rate of 1% in 10 000 h

Temperature, °C
Stress, MPa
550
160
600
120
650
90
700
60
800
20
Recommended Maximum Service Temperature
(Oxidising conditions)

Continuous Service 925oC
Intermittent Service 870oC

3. Properties at Sub-Zero Temperatures
( CS 316 )
Temperature
Proof Strength (0.2% Offset)
Tensile Strength
Impact Strength (Charpy V-Notch)
°C
MPa
MPa
J
-78
400
820
120
-161
460
1150
165
-196
580
1300
155
4. Corrosion Resistance

4.1 Aqueous
For specific conditions, consult VRN technical staff. As a rough guide, the following examples are given
for pure acid-water mixtures.
Temperature °C
Concentration, (-% by mass)
Sulphuric Acid
Nitric Acid
Phosphoric Acid
Formic Acid
20
10 20 40 60 80 100
0 1 2 2 1 0
0 0 0 0 0 1
0 0 0 0 1 2
0 0 0 1 1 0
80
10 20 40 60 80 100
2 2 2 2 2 2
0 0 0 1 1 2
0 0 2 2 1 1
0 2 2 2 2 0
Key: 0 = resistant - corrosion rate less than 100 >mm/year
1 = partly resistant - corrosion rate 100 m to 1000 >mm/year
2 = non resistant - corrosion rate more than 1000 mm/year
4.2 Atmospheric
The performance of CS 316 compared with other metals in various environments is shown in the
following table. Corrosion rate is based on a 5 year exposure.
Environment
Rural
Marine
Marine Industrial
Corrosion Rate (µm/year)
SX 314Aluminium-3SMild Steel
0.00250.0255.8
0.00760.42434.0
0.0051068646.2
Note: For corrosion resistance of CS 316 relative to other types, see the section in Comparative Data.

http://askzn.co.za/draft2/tech/tech_grade_316.htm

4.3.1 Annealing. Heat from 1 010oC to 1 120oC and cool rapidly in air or water. The best corrosion
resistance is obtained when the final annealing temperature is above 1 070oC.

4.3.2 Stress relieving. Heat from 200 - 400oC and air cool.

4.3.3 Hot working
Initial forging and pressing: 1150 - 1200oC
Finishing temperature: above 900oC
For upsetting operations, forgings
should be finished between: 930 and 980oC
All hot working operations should be followed by annealing.

Note: Soaking times to ensure uniformity of temperature are up to 12 times that required for the same thickness of mild steel.

Cold Working

CS 316 / 316L, being extremely tough and ductile, can be readily fabricated by cold working. Typical operations include bending, forming, deep drawing and upsetting.

[Cheechako]

Originally Posted by artisanmach

FYI. info on 316ss
read the very last comment...cold work, just form it...
. When there is a danger of corrosion in the heat-affected zones of weldments, the low-carbon variety CS 316L should be used.
4.3.1 Annealing. Heat from 1 010oC to 1 120oC and cool rapidly in air or water. The best corrosion
resistance is obtained when the final annealing temperature is above 1 070oC.

4.3.3 Hot working
Initial forging and pressing: 1150 - 1200oC
Finishing temperature: above 900oC
For upsetting operations, forgings
should be finished between: 930 and 980oC
All hot working operations should be followed by annealing.

Note: Soaking times to ensure uniformity of temperature are up to 12 times that required for the same thickness of mild steel.

Cold Working

CS 316 / 316L, being extremely tough and ductile, can be readily fabricated by cold working. Typical operations include bending, forming, deep drawing and upsetting.

Yep. While SS can be welded, brushed and left, as may be the case for fishing towers etc. It will be more prone to corrosion, less so with TIG welding done by a good welder so the heat effected zone and bead is small. WOrked Aerospace welding problems for 30 years. In Aero, it is rare to not specify annealing or similar after welding, and fatigue cracking is far higher if not treated.

[Sailorbob8599]

Originally Posted by Dave_S

Just bend it.

Hold the short end in the vice, place a close fit pipe over the other end and bend it in one smooth action and leave a good radius on the inside bend.

Drill the holes after bending. Use a pilot hole, don't let the drill stop drilling.

The original post states he has already drilled the holes.

[Steel sails]

I am with the just bend it crowd.
316 flat bar is almost certainly supplied in the annealed condition and more than likely its 316L
316 is not a hardenable alloy so no need to worry about it being hard or 1/2 Hard etc.
Regards
Paul

[Dave_S]

Originally Posted by Sailorbob8599

The original post states he has already drilled the holes.

Fair enough but the holes won't line up after bending, you can't change that.

[Cheechako]

Most all flat bar receives a final cold rolling pass at the mill. That keeps the finish reasonable and the tolerances good. But yes it wont real work harden it that much. There used to be some harder bar shapes out there that received more cold work but they would likely be specified that way when sold.

[bigman1]

With 316 that thick you need oxy gas setup,if you worried about cracking why not go to 1/2" mild steel and paint it with galvanising paint some amazing new cold galvanising stuff out there.Cheers.

[hpeer]

If there is some special cold galvanizing that won’t rust I’d love to hear about it. On our big boat the first owner had all mild steel chain plates replaced with Ss. I’m considering doing the same in our small boat, or at least welding on some ss tangs.

[bigman1]

Its called zinga cold galvanising has built in primer, gets good online reviews, it's on uk eBay
you might find it on ebay USA.

[Cheechako]

It's not cracking with a 45 degree bend, even if the bend radius is less than the advised 3T.
Are we still talking about this? I would thought they were bent and on the boat by now.....

[seabreez]

Originally Posted by svninkasi

Run by a local welding or machine shop. They will do it why you wait and probly for free.

I second the motion here! Do it right the first time, instead of redoing it or looking at the crooked piece every time you board the boat...

[Rick Williams]

I already told you guys how to do this. My daughter and I replaced all our chain plates on our 38' ketch by starting with unpolished flat stock which we bent using a cheap press from Harbor Freight ($102.00) and polished them ourselves. Took maybe 3 days total and using the old ones as patterns (and later backing plates...) they came out perfectly

[Mike Banks]

Avoid the problem altogether. Fit twin back stays--no more running back stays, much stronger, one can be an aerial for your HF--something to hang on to when boarding a dinghy, something to tie a rain catcher to--can even be part of the support for a Bimini--

[Jim Cate]

Originally Posted by Mike Banks

Avoid the problem altogether. Fit twin back stays--no more running back stays, much stronger, one can be an aerial for your HF--something to hang on to when boarding a dinghy, something to tie a rain catcher to--can even be part of the support for a Bimini--

HOw does going to twin backstays remove the need for runners?

Runners are support for the middle part of the mast, usually in way of an inner forestay or a fractional jib. Twin masthead backstays support the mast head only.

And depending upon wire size and chainplate construction, twin stays are not necessarily any stronger than a single one.

Don't see how your advice will help the OP... and by now surely he has bent the bloody things!

Jim