Two functions for the steel

High quality and high performance of the steel in the bucket is necessary for reliable and lasting functions of the bucket. Strong and hard steel grades also results in higher payload capacity.

The steel has two main functions, to carry the load and to resist abrasion. SSAB Oxelösund has the widest programme of steel grades from the very thin to the heavy dimensions of abrasion resistant steel grades:

• HARDOX 400
• HARDOX 450
• HARDOX 500
• HARDOX 600

Example of steel grades in a medium size Heavy Duty Excavator Bucket:

Part	Steel grade	Thickness (mm)	Weight (%)
Floor*	HARDOX 400	6-16	16%
Shell*	HARDOX 400	6-16	16%
Side sheets	HARDOX 400	6-12	7%
Beam	HARDOX 400	6-12	12%
Attachment	HARDOX 400	20-40	5%
Cutting edge	HARDOX 500	30-50	18%
Side cutters, cheek plates	HARDOX 500	16-40	16%
Wear bars, wear plates	HARDOX 500	20-40	10%

  *) The floor plate is either separated from the shell plate or integrated with the shell plate (see below).

HARDOX wear plates can be used for all parts exposed to wear.

For large buckets with thick edges (more than 60 mm), it is important to consider the function of the edge and the floor as structural parts. Thus, it is common to utilise the wear bars (as shown in the picture) to support the load from side to side. Due to the large forces, a critical design area is the support for the bolt-on edge, teeths and segments.

The weight of a general purpose excavator bucket is about 0.8-1.0 kg/litre (as nominal ISO/SAE volume). A general purpose loader bucket has a weight of about 0.5-0.7 kg/litre.

Production

The SSAB steel works in Oxelösund, Sweden is based on very pure iron ore from the north of Sweden and have the most advanced metallurgy processing.

The most powerful rolling mill in the world gives through-thickness deformation and the highest available precision.

Heat treatment of the plates is done in the most advanced quenching facilities, specially designed for high quality quenched and tempered steels. 
The cost and time of bucket production is not that much more than for ordinary steels. There is extensive information and technical support available from SSAB Oxelösund.

The critical parts in manufacturing are the parts exposed to the heavy wear, that is the teeth, the segments, the cutting edge and the side cutters. Thus, the cutting, drilling, maching and welding operations of those parts are extremely important.

The combination of high purity and low content of alloying elements and thus low carbon equivalents for the steel types, make the HARDOX wear plate eminently well suited for cutting, welding and machining: 

• Shearing, Cutting
• Welding
• Machining

Repairment

The repairment of buckets is an important issue. That is why we put that in a separate Infopac: Infopac Bucket Repair.

For more information, please contact:
techsupport@ssab.com