Steel strapping - Co

Report
Strapping Training
Ersoy Tuncay – 2012
GENERAL COMPARISON
STRAP TYPES
TENSILE STRENGTH
ELONGATION
ELONGATION
N/MM2
WORKING RANGE
AT BREAK
PP
PP-Machine Grade
DYLASTIC
DYLASTIC T
300
350
6%
3,5%
26%
18%
PET
PET - High Strength
TENAX
TENAX HS
400
450
2%
2%
15 - 20%
13%
STEEL STRAP
APEX
STEEL STRAP
MAGNUS
COMPOSITE STRAPPING CO-STRAP
850
1050
n/a
0,2%
0,2%
4%
13%
13%
12 - 15%
RANGE OF USEs OF STRAPPING
Chains, wire rope, Woven
polyester, etc.
Weight of Application
LASHING
STEEL Strap
COMPOSITE
STRAPPING
PET Strap
PPStrap / Stretch film
Market Volume
Strapping types in General
 Steel strapping:
 Magnus-strap
1000 - 1070 Newton/mm2
 Heavy packs
 Apex-strap 780 - 900 Newton/mm2
 Simple / medium typ applications / cost reductions
 Plastic strapping:
 PET strap
 PET high strength
 Normal PET
16 – 32 mm (6.000 – 18.800 Newton)
9 – 16 mm (2.000 – 5.000 Newton)
 PP strapping
 Machine strapping
 Manual strapping
5 – 16 mm (500 – 4.500 Newton)
11 - 15 mm (2.000 – 3.000 Newton)
 Polyester Corded Strapping
 Manuel Application
 As strong as Steel Strap and excellent retain tension performance ( 2000 kgf Break
Strength)
STRAPPING NORMS AND STANDARTS
Ambalaj Çemberi ile İlgili Normlar
Sıra No
Norm Kodu
Açıklama
1
EN 13246
2
EN 13247
Specification of Tensional Steel Strapping
Specification for tensional steel strapping for lifting, lashing and securing of loads
3
EN 13394
Specification for Non-Metallic tensional strapping
4
EN 13891
Tensional strapping — Guide to selection and use of tensional strapping
5
ASTM D 3950
Standard Specification for Strapping, Nonmetallic (and Joining Methods)
6
ASTM D 3953
Standard Specification for Strapping, Flat Steel and Seals
STRAP PROPERTIES
– Strength
• Tensile Strength
• Break Strength
– Joint Efficiency
– Working Range
– Retained Tension
– Elongation and Recovery
– Impact Resistance
Tensile Strength
Tensile strength is characteristic of a type of material and the way it has
been processed
PP
320 N/mm2
PET
400 N/mm2
PET
450 N/mm2
Apex STEEL
850 N/mm2
Magnus STEEL
1050 N/mm2
Composite Strapping
n/a ( No homogenous Crossection)
Break Strength
Break strength is characteristic of a specific strap.
It is the product of cross-sectional area and tensile strength
PET 19mm x 1.27mm x 450N/mm2 = ~ 11,000N
Magnus Steel Strap 19mmx0.63mm
= 19mm x 0.63mm x 1.050N/mm2 = ~ 12,500N
Joint Strengts
The joint strength determines the loop strength!
Examples for PET Strapping:
 Pneumatic hand tools
45 to 60% (Stick to min for variations in air pressure
and flow or PET sheet material.)
 Battery Charged Tool
60 to 75% (Depending on strap type sheet single
extruded)
 Machines
80 to 90 % single extruded
Joint Strength of Composite
Strapping
JOINT EFFICIENCY of POLYESTER CORDED COMPOSITE
STRAPS
: 80 – 90 %
Joint Strength of Steel Strapping at Different
Joint Types
Retained Tension
Retained tension is the strap tension that remains
over time
Applied tension is the tension that is initially
applied to a strap
Tension decay is the tension that is lost over time
Retained tension :
• Steel 90 to 95%
• PET 65 to 75%
• PP
25 to 35%
• Composite Strap 80 to 90%
The size of the strap does not affect the RT.
WORKING RANGE
Working Range
 Working range of PET and steel strap are about 50% of their
break strengths.
 Working range of PP is about 35% of its break strength.
 Working range elongation is the main reason why PET is tougher
than steel.
Steel
0.2 -0.3 %
PET
2 - 4%
PP- Special
6%
Composite Strapping 4 – 6%
Impact resistance
 Impact resistance is measured by work (energy necessary) to break/deform the
strap.
Calculation:
Working range (%) x Joint strength (N) x Working range
elongation (%)
 Comparison between Steel Strap 32 x 0,8 applied with a double notch seal, and a PET 19
x1,27mm PET Strap with battery tool :
 Apex 31,75 x 0,8 mm BS is 20.000Nx 70% JS = 14.000 N
 50% x 14.000 x 0,3 = 2.100 Nmm
 PET 19,05 x 1,27 BS is 10.000 N x 75% JS = 7.500 N
 50% x 7.500 x 4 =
15.000 Nmm
So the PET Strap and also COMPOSITE STRAPs in this case is half
the strength but 7 ( Seven) times tougher!!!!
Steel Strap Break Strength (BS) = 11,120 Newtons:
PET Strap BS = 5,560 Newtons
LOAD - ELONGATION CURVE
3,000 / 13345
3,000
Steel Strap
POUNDS / NEWTONS
2,500 / 11,120
2,500
2,000 / 8,896
2,000
Composite /
PET Strap
Work to break Steel
400 units
WORK = 1/2x0.3x2000
300 units
1.500 / 6,672
1,500
1,000 / 4,448
1,000
Work to break Composite /
PET Strap
WORK = 1/2x1000x4
2000 units
500 / 2,224 500
0
1
2
3
4
ELONGATION
5
6
7
8
Choosing Your Strap
Factors affecting strap choice
Function or purpose of the strap
Package characteristics
Shipping or handling considerations
 Strapping may perform the following functions:
package reinforcement, carton closure, securement, unitization, baling,
bundling, bracing, paletization, compression retention and pilferage
reduction.
 Package characteristics that influence strap selection are: weight, stability,
rigidity, integrity and sharpness of the edges (sharp edges may demand
heavier strapping or corner protection).
 Shipping considerations that affect the choice of strapping include: how far
the package is shipped; how it’s handled by both the shipper and receiver;
and where and how it’s stored.
EQUIPMENT BY PACKAGE TYPES
 Shape:
 Rectangular Normal hand-tools / Machines
 Round
Push type tools / (Machines)
 Weight:
 How much mass has to be held together?
 Weight
 Package stability:
Straps
 Is the product stabile by itself, is the stacking stabile?
 Strapping to hold pack on pallet, or to hold pack together?
 What happens when a strap breaks?
 Costs
 Safety
 Product edges:
 Does strap damage product? Corner-protection
 Does product damage strap?
 Need to distribute more tension?
Transport (Intern/Extern)
You may ask yourself the following questions:
 How is the pack lifted / handled?
 Forklift, magnetic overhead crane, roller-conveyor, etc.
 How long is the pack in storage?
 Shrinking, corrosion.
 Conditions of storage?
 Moisture, dust, sunlight, heat, ice, etc.
 Way of storage?
 Stacked, in racks
 Way of transport?
 Truck, train (shunting), ship, airfreight.
 Distance of transport?
 Domestic or Export, the more transport actions, the higher the risk .
At the end customer
 How does the end customer handle the package?
 Forklift truck, roller conveyor, magnetic crane, etc.
 How / when does he take the packaging apart?
 Any hazards, complications?
 Is there intermediate storage?
 Many more handlings, very long storage times.
 Does the pack get resold?
 Needs to be broken down to smaller units.
 Try to think further …..
Types of Steel Strapping
Apex
is a cold-rolled, low carbon steel strapping. It is
used for light and medium duty loads that needhigh strength and high
retained tension but are not subject to impacts or shock.
Magnus
steel strapping is made from higher-carbon, cold-rolled, heat treated steel. It is
used on heavy/very heavy loads that require high strength and are subject to
impacts andshock during transit and handling.
USLM
steel strapping is made from higher-carbon, cold-rolled, heat treated steel. It is
used on very heavy/extreme loads.
Chemical Analysis of Steel Strap
Types
C [%]
Mn [%]
APEX
0,13 - 0,17
0,45 - 0,70
MAGNUS
0,29 - 0,33
1,25 - 1,45
USLM
0,44 - 0,46
0,70 - 0,90
Why waffled strap
Advantages:
A thicker strap with a lower Gram / Meter (Cheaper)
Stiffer, good feeding through chutes
Disadvantages at heavy waffling :
Longer weldtime, or weaker weld.
Less meterage per Kg.
Tension-wheel grips in “air”
A smaller smooth strap can replace a wider waffled strap.
TRUCK TRANSPORTATION
RAILWAY TRANSPORTATION
SEA TRANSPORTATION
NUMBER of STRAPS REQUIRED
CALCULATION
Minimum Number of Straps
=(Load Weight x G Force x 1,5 )/System Strength
1,5 : Safety Factor
Safety Factor can be varied according the transportation mode
and also type of the product.
System Strength of Composite Strapping = 1,6 x Nominal
Break Strength
Çember Miktarı Hesaplama Örneği :




Palet Weight : 3000 kg
Strap Used : CS32ESTR Composite Strap
Break Strength of the Strap : 1600 kg
System Strength of the Strap : 2560 kg
 Safety factor : 1,5
 Minimum # of Straps should be on the Pallet
= 3000 x 1,5 / 2560
= 1,76
Two ( 2 ) Straps
Steel Strapping
vs
PET / Composite Strapping
Steel Strapping has :
Advantages
Disadvantages
High Corner Strentgth
Low Elasticity
High Breaking Strength
Low Elongation Recovery
Tensionable with hand, pneumatic or fully
automatic machines
Low Shock Absorbency ( Impact )
High Static System Strength if closed properly
Low3 Dynamic System Strength
Can be tensioned manually or sealed with battery Dangerous to users , Damage to products
tensioner
Also fully automatic possible
Expensive than PET / Composite strapping
Thank You
Ersoy Tuncay / 2012

similar documents